diff --git a/docs/dataset.rst b/docs/dataset.rst
index fcee84b..91cc959 100644
--- a/docs/dataset.rst
+++ b/docs/dataset.rst
@@ -1,24 +1,30 @@
 `pycldf.dataset`
 ================
 
+.. py:currentmodule:: pycldf.dataset
+
 The core object of the API, bundling most access to CLDF data, is
-the :class:`pycldf.Dataset` . In the following we'll describe its
+the :class:`.Dataset` . In the following we'll describe its
 attributes and methods, bundled into thematic groups.
 
 
 Dataset initialization
 ~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pycldf.dataset.Dataset
+.. autoclass:: Dataset
    :members: __init__, in_dir, from_metadata, from_data
 
 
 Accessing dataset metadata
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: directory, module, version, metadata_dict, properties, bibpath, bibname
+.. autoproperty:: Dataset.directory
+.. autoproperty:: Dataset.module
+.. autoproperty:: Dataset.version
+.. autoproperty:: Dataset.metadata_dict
+.. autoproperty:: Dataset.properties
+.. autoproperty:: Dataset.bibpath
+.. autoproperty:: Dataset.bibname
 
 
 Accessing schema objects: components, tables, columns, etc.
@@ -26,18 +32,19 @@ Accessing schema objects: components, tables, columns, etc.
 
 Similar to *capability checks* in programming languages that use
 `duck typing <https://en.wikipedia.org/wiki/Duck_typing>`_, it is often necessary
-to access a datasets schema, i.e. its tables and columns to figure out whether
-the dataset fits a certain purpose. This is supported via a `dict`-like interface provided
-by :class:`pycldf.Dataset`, where the keys are table specifiers or pairs (table specifier, column specifier).
+to access a datasets schema, i.e. its tables and columns, to figure out whether
+the dataset fits a certain purpose. This is supported via a
+`mapping <https://docs.python.org/3/glossary.html#term-mapping>`_-like interface provided
+by :class:`.Dataset`, where the keys are table specifiers or pairs (table specifier, column specifier).
 A *table specifier* can be a table's component name or its `url`, a *column specifier* can be a column
 name or its `propertyUrl`.
 
-* check existence with `in`:
+* check existence with ``in``:
 
     .. code-block:: python
 
-        if 'ValueTable' in dataset: pass
-        if ('ValueTable', 'Language_ID') in dataset: pass
+        if 'ValueTable' in dataset: ...
+        if ('ValueTable', 'Language_ID') in dataset: ...
 
 * retrieve a schema object with item access:
 
@@ -46,58 +53,69 @@ name or its `propertyUrl`.
         table = dataset['ValueTable']
         column = dataset['ValueTable', 'Language_ID']
 
-* retrieve a schema object or a default with `.get`:
+* retrieve a schema object or a default with :meth:`.Dataset.get`:
 
     .. code-block:: python
 
         table_or_none = dataset.get('ValueTableX')
         column_or_none = dataset.get(('ValueTable', 'Language_ID'))
 
-* remove a schema object with `del`:
+* remove a schema object with ``del``:
 
     .. code-block:: python
 
         del dataset['ValueTable', 'Language_ID']
         del dataset['ValueTable']
 
-Note: Adding schema objects is **not** supported via key assignment, but with a set of specialized
-methods described in :ref:`Editing metadata and schema`.
+.. note::
 
+    Adding schema objects is **not** supported via key assignment, but with a set of specialized
+    methods described in :ref:`Editing metadata and schema`.
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: tables, components, __getitem__, __contains__, get, get_foreign_key_reference, column_names, readonly_column_names
+.. autoproperty:: Dataset.tables
+.. autoproperty:: Dataset.components
+.. automethod:: Dataset.__getitem__
+.. automethod:: Dataset.__delitem__
+.. automethod:: Dataset.__contains__
+.. automethod:: Dataset.get
+.. automethod:: Dataset.get_foreign_key_reference
+.. autoproperty:: Dataset.column_names
+.. autoproperty:: Dataset.readonly_column_names
 
 
 Editing metadata and schema
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 In many cases, editing the metadata of a dataset is as simple as editing
-:meth:`~pycldf.dataset.Dataset.properties`, but for the somewhat complex
+:meth:`.Dataset.properties`, but for the somewhat complex
 formatting of provenance data, we provide the shortcut
-:meth:`~pycldf.dataset.Dataset.add_provenance`.
+:meth:`.Dataset.add_provenance`.
 
-Likewise, `csvw.Table` and `csvw.Column` objects in the dataset's schema can
+Likewise, ``csvw.Table`` and ``csvw.Column`` objects in the dataset's schema can
 be edited "in place", by setting their attributes or adding to/editing their
-`common_props` dictionary.
+``common_props`` dictionary.
 Thus, the methods listed below are concerned with adding and removing tables
 and columns.
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: add_table, remove_table, add_component, add_columns, remove_columns, rename_column, add_foreign_key, add_provenance,
+.. automethod:: Dataset.add_table
+.. automethod:: Dataset.remove_table
+.. automethod:: Dataset.add_component
+.. automethod:: Dataset.add_columns
+.. automethod:: Dataset.remove_columns
+.. automethod:: Dataset.rename_column
+.. automethod:: Dataset.add_foreign_key
+.. automethod:: Dataset.add_provenance
 
 
 Adding data
 ~~~~~~~~~~~
 
-The main method to persist data as CLDF dataset is :meth:`~pycldf.Dataset.write`,
+The main method to persist data as CLDF dataset is :meth:`.Dataset.write`,
 which accepts data for all CLDF data files as input. This does not include
-sources, though. These must be added using :meth:`~pycldf.Dataset.add_sources`.
+sources, though. These must be added using :meth:`.Dataset.add_sources`.
+
+.. automethod:: Dataset.add_sources
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: add_sources
 
 
 Reading data
@@ -105,30 +123,31 @@ Reading data
 
 Reading rows from CLDF data files, honoring the datatypes specified in the schema,
 is already implemented by `csvw`. Thus, the simplest way to read data is iterating
-over the `csvw.Table` objects. However, this will ignore the semantic layer provided
+over the ``csvw.Table`` objects. However, this will ignore the semantic layer provided
 by CLDF. E.g. a CLDF languageReference linking a value to a language will be appear
-in the `dict` returned for a row under the local column name. Thus, we provide several
+in the ``dict`` returned for a row under the local column name. Thus, we provide several
 more convenient methods to read data.
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: iter_rows, get_row, get_row_url, objects, get_object
+.. automethod:: Dataset.iter_rows
+.. automethod:: Dataset.get_row
+.. automethod:: Dataset.get_row_url
+.. automethod:: Dataset.objects
+.. automethod:: Dataset.get_object
 
 
 Writing (meta)data
 ~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: write, write_metadata, write_sources
+.. automethod:: Dataset.write
+.. automethod:: Dataset.write_metadata
+.. automethod:: Dataset.write_sources
 
 
 Reporting
 ~~~~~~~~~
 
-.. autoclass:: pycldf.Dataset
-   :noindex:
-   :members: validate, stats
+.. automethod:: Dataset.validate
+.. automethod:: Dataset.stats
 
 
 Dataset discovery
@@ -147,7 +166,7 @@ Sources
 ~~~~~~~
 
 When constructing sources for a CLDF dataset in Python code, you may pass
-:class:`pycldf.Source` instances into :meth:`pycldf.Dataset.add_sources`,
+:class:`pycldf.Source` instances into :meth:`Dataset.add_sources`,
 or use :meth:`pycldf.Reference.__str__` to format a row's `source` value
 properly.
 
@@ -169,8 +188,19 @@ in its `sources` attribute.
 Subclasses supporting specific CLDF modules
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. note::
+
+    Most functionality provided through properties and methods described below is implemented via
+    the :mod:`pycldf.orm` module, and thus subject to the limitations listed at `<./orm.html>`_
+
 .. autoclass:: pycldf.Generic
     :members:
 
 .. autoclass:: pycldf.Wordlist
     :members:
+
+.. autoclass:: pycldf.StructureDataset
+    :members:
+
+.. autoclass:: pycldf.TextCorpus
+    :members:
diff --git a/setup.cfg b/setup.cfg
index 6df6680..79ed27c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -40,6 +40,8 @@ install_requires =
     clldutils>=3.9
     uritemplate>=3.0
     python-dateutil
+    # pybtex requires setuptools, but doesn't seem to declare this.
+    setuptools
     pybtex
     requests
     newick
diff --git a/src/pycldf/components/ExampleTable-metadata.json b/src/pycldf/components/ExampleTable-metadata.json
index f62f56e..f3faec9 100644
--- a/src/pycldf/components/ExampleTable-metadata.json
+++ b/src/pycldf/components/ExampleTable-metadata.json
@@ -61,6 +61,14 @@
                 "dc:description": "References the language of the translated text",
                 "datatype": "string"
             },
+            {
+                "name": "LGR_Conformance",
+                "required": false,
+                "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#lgrConformance",
+                "dc:extent": "singlevalued",
+                "dc:description": "The level of conformance of the example with the Leipzig Glossing Rules",
+                "datatype": {"base": "string", "format": "WORD_ALIGNED|MORPHEME_ALIGNED"}
+            },
             {
                 "name": "Comment",
                 "required": false,
diff --git a/src/pycldf/components/ParameterNetwork-metadata.json b/src/pycldf/components/ParameterNetwork-metadata.json
new file mode 100644
index 0000000..f069e77
--- /dev/null
+++ b/src/pycldf/components/ParameterNetwork-metadata.json
@@ -0,0 +1,45 @@
+{
+  "url": "parameter_network.csv",
+  "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#ParameterNetwork",
+  "dc:description": "Rows in this table describe edges in a network of parameters.",
+  "tableSchema": {
+    "columns": [
+      {
+        "name": "ID",
+        "required": true,
+        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+        "datatype": {
+          "base": "string",
+          "format": "[a-zA-Z0-9_\\-]+"
+        }
+      },
+      {
+        "name": "Description",
+        "required": false,
+        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#description",
+        "datatype": "string"
+      },
+      {
+        "name": "Target_Parameter_ID",
+        "required": true,
+        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#targetParameterReference",
+        "dc:description": "References the target node of the edge.",
+        "datatype": "string"
+      },
+      {
+        "name": "Source_Parameter_ID",
+        "required": true,
+        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#sourceParameterReference",
+        "dc:description": "References the source node of the edge.",
+        "datatype": "string"
+      },
+      {
+        "name": "Edge_Is_Directed",
+        "required": false,
+        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#edgeIsDirected",
+        "dc:description": "Flag signaling whether the edge is directed or undirected.",
+        "datatype": {"base": "boolean", "format": "Yes|No"}
+      }
+    ]
+  }
+}
diff --git a/src/pycldf/dataset.py b/src/pycldf/dataset.py
index 2b73c6f..04bd453 100644
--- a/src/pycldf/dataset.py
+++ b/src/pycldf/dataset.py
@@ -30,13 +30,16 @@
 
 __all__ = [
     'Dataset', 'Generic', 'Wordlist', 'ParallelText', 'Dictionary', 'StructureDataset',
-    'iter_datasets', 'sniff', 'SchemaError', 'ComponentWithValidation']
+    'TextCorpus', 'iter_datasets', 'sniff', 'SchemaError', 'ComponentWithValidation']
 
 MD_SUFFIX = '-metadata.json'
 ORM_CLASSES = {cls.component_name(): cls for cls in orm.Object.__subclasses__()}
 TableType = typing.Union[str, Table]
 ColType = typing.Union[str, Column]
 PathType = typing.Union[str, pathlib.Path]
+TableSpecType = typing.Union[str, Link, Table]
+ColSPecType = typing.Union[str, Column]
+SchemaObjectType = typing.Union[TableSpecType, typing.Tuple[TableSpecType, ColSPecType]]
 
 
 class SchemaError(KeyError):
@@ -135,8 +138,8 @@ class Dataset:
 
     def __init__(self, tablegroup: csvw.TableGroup):
         """
-        A :class:`~pycldf.dataset.Dataset` is initialized passing a `TableGroup`. For convenience \
-        methods to get such a `TableGroup` instance, see the factory methods
+        A :class:`~pycldf.dataset.Dataset` is initialized passing a `TableGroup`. The following \
+        factory methods obviate the need to instantiate such a `TableGroup` instance yourself:
 
         - :meth:`~pycldf.dataset.Dataset.in_dir`
         - :meth:`~pycldf.dataset.Dataset.from_metadata`
@@ -320,7 +323,7 @@ def bibname(self) -> str:
     # Accessing schema objects (components, tables, columns, foreign keys)
     #
     @property
-    def tables(self) -> list:
+    def tables(self) -> typing.List[Table]:
         """
         :return: All tables defined in the dataset.
         """
@@ -329,7 +332,7 @@ def tables(self) -> list:
     @property
     def components(self) -> typing.Dict[str, csvw.Table]:
         """
-        :return: Mapping of component name to table obejcts as defined in the dataset.
+        :return: Mapping of component name to table objects as defined in the dataset.
         """
         res = collections.OrderedDict()
         for table in self.tables:
@@ -362,27 +365,29 @@ def primary_table(self) -> typing.Union[str, None]:
             except ValueError:
                 return None
 
-    def __getitem__(self, item) -> typing.Union[csvw.Table, csvw.Column]:
+    def __getitem__(self, item: SchemaObjectType) -> typing.Union[csvw.Table, csvw.Column]:
         """
         Access to tables and columns.
 
-        If a pair (table-spec, column-spec) is passed as `item`, a Column will be
-        returned, otherwise `item` is assumed to be a table-spec.
+        If a pair (table-spec, column-spec) is passed as ``item``, a :class:`csvw.Column` will be
+        returned, otherwise ``item`` is assumed to be a table-spec, and a :class:`csvw.Table` is
+        returned.
 
         A table-spec may be
 
-        - a CLDF ontology URI matching the dc:conformsTo property of a table
+        - a CLDF ontology URI matching the `dc:conformsTo` property of a table
         - the local name of a CLDF ontology URI, where the complete URI matches the \
-          the dc:conformsTo property of a table
-        - a filename matching the `url` property of a table
+          the `dc:conformsTo` property of a table
+        - a filename matching the `url` property of a table.
 
         A column-spec may be
 
-        - a CLDF ontology URI matching the propertyUrl of a column
+        - a CLDF ontology URI matching the `propertyUrl` of a column
         - the local name of a CLDF ontology URI, where the complete URI matches the \
-          propertyUrl of a column
-        - the name of a column
+          `propertyUrl` of a column
+        - the name of a column.
 
+        :param item: A schema object spec.
         :raises SchemaError: If no matching table or column is found.
         """
         if isinstance(item, tuple):
@@ -424,14 +429,19 @@ def __getitem__(self, item) -> typing.Union[csvw.Table, csvw.Column]:
 
         raise SchemaError('Dataset has no column "{}" in table "{}"'.format(column, t.url))
 
-    def __delitem__(self, key):
-        thing = self[key]
+    def __delitem__(self, item: SchemaObjectType):
+        """
+        Remove a table or column from the datasets' schema.
+
+        :param item: See  :meth:`~pycldf.dataset.Dataset.__getitem__`
+        """
+        thing = self[item]
         if isinstance(thing, Column):
-            self.remove_columns(self[key[0]], thing)
+            self.remove_columns(self[item[0]], thing)
         else:
             self.remove_table(thing)
 
-    def __contains__(self, item) -> bool:
+    def __contains__(self, item: SchemaObjectType) -> bool:
         """
         Check whether a dataset specifies a table or column.
 
@@ -439,7 +449,9 @@ def __contains__(self, item) -> bool:
         """
         return bool(self.get(item))
 
-    def get(self, item, default=None) -> typing.Union[csvw.Table, csvw.Column, None]:
+    def get(self,
+            item: SchemaObjectType,
+            default=None) -> typing.Union[csvw.Table, csvw.Column, None]:
         """
         Acts like `dict.get`.
 
@@ -1189,10 +1201,67 @@ def primary_table(self):
 
 
 class StructureDataset(Dataset):
+    """
+    Parameters in StructureDataset are often called "features".
+
+    .. seealso:: `<https://github.com/cldf/cldf/tree/master/modules/StructureDataset>`_
+    """
     @property
     def primary_table(self):
         return 'ValueTable'
 
+    @functools.cached_property
+    def features(self):
+        """
+        Just an alias for the parameters.
+        """
+        return self.objects('ParameterTable')
+
+
+class TextCorpus(Dataset):
+    """
+    In a `TextCorpus`, contributions and examples have specialized roles:
+
+    - Contributions are understood as individual texts of the corpus.
+    - Examples are interpreted as the sentences of the corpus.
+    - Alternative translations are provided by linking "light-weight" examples to "full", main
+      examples.
+    - The order of sentences may be defined using a `position` property.
+
+    .. seealso:: `<https://github.com/cldf/cldf/tree/master/modules/TextCorpus>`_
+
+    .. code-block:: python
+
+        >>> crp = TextCorpus.from_metadata('tests/data/textcorpus/metadata.json')
+        >>> crp.texts[0].sentences[0].cldf.primaryText
+        'first line'
+        >>> crp.texts[0].sentences[0].alternative_translations
+        [<pycldf.orm.Example id="e2-alt">]
+    """
+    @property
+    def primary_table(self):
+        return 'ExampleTable'
+
+    @functools.cached_property
+    def texts(self) -> typing.Union[None, DictTuple]:
+        # Some syntactic sugar to access the ORM data in a concise and meaningful way.
+        if 'ContributionTable' in self:
+            return self.objects('ContributionTable')
+
+    def get_text(self, tid):
+        if 'ContributionTable' in self:
+            return self.get_object('ContributionTable', tid)
+
+    @property
+    def sentences(self) -> typing.List[orm.Example]:
+        res = list(self.objects('ExampleTable'))
+        if ('ExampleTable', 'exampleReference') in self:
+            # Filter out alternative translations!
+            res = [e for e in res if not e.cldf.exampleReference]
+        if ('ExampleTable', 'position') in self:
+            return sorted(res, key=lambda o: o.cldf.position)
+        return res  # pragma: no cover
+
 
 class ComponentWithValidation:
     def __init__(self, ds: Dataset):
diff --git a/src/pycldf/db.py b/src/pycldf/db.py
index 68b5582..0315324 100644
--- a/src/pycldf/db.py
+++ b/src/pycldf/db.py
@@ -3,10 +3,10 @@
 
 To make the resulting SQLite database useful without access to the datasets metadata, we
 use terms of the CLDF ontology for database objects as much as possible, i.e.
-- table names are component names (e.g. "ValueTable" for a table with propertyUrl \
-  http://cldf.clld.org/v1.0/terms.rdf#ValueTable)
+- table names are component names (e.g. ``ValueTable`` for a table with `propertyUrl` \
+  ``http://cldf.clld.org/v1.0/terms.rdf#ValueTable``)
 - column names are property names, prefixed with "cldf" + UNDERSCORE (e.g. a column with \
-  propertyUrl http://cldf.clld.org/v1.0/terms.rdf#id will be "cldf_id" in the database)
+  `propertyUrl` ``http://cldf.clld.org/v1.0/terms.rdf#id`` will be ``cldf_id`` in the database)
 
 This naming scheme also extends to automatically created association tables. I.e. when a
 table specifies a list-valued foreign key, an association table is created to implement this
@@ -14,7 +14,7 @@
 - the url properties of the tables in this relationship or of
 - the component names of the tables in the relationship.
 
-E.g. a list-valued foreign key from the FormTable to the ParameterTable will result in an
+E.g. a list-valued foreign key from `FormTable` to `ParameterTable` will result in an
 association table
 
 .. code-block:: sql
@@ -50,6 +50,7 @@
 
 from pycldf.terms import TERMS
 from pycldf.sources import Reference, Sources, Source
+from pycldf import Dataset
 
 __all__ = ['Database']
 
@@ -97,9 +98,9 @@ def translate(d: typing.Dict[str, TableTranslation], table: str, col=None) -> st
     """
     Translate a db object name.
 
-    :param d: `dict` mapping table urls to `TableTranslation` instances.
+    :param d: ``dict`` mapping table urls to `TableTranslation` instances.
     :param table: The table name of the object to be translated.
-    :param col: Column name to be translated or `None` - so `table` will be translated.
+    :param col: Column name to be translated or `None` - so ``table`` will be translated.
     :return: Translated name.
     """
     if col:
@@ -121,16 +122,16 @@ def clean_bibtex_key(s):
 
 class Database(csvw.db.Database):
     """
-    Extend the functionality provided by `csvw.db.Database` by
+    Extend the functionality provided by ``csvw.db.Database`` by
 
     - providing consistent naming of schema objects according to CLDF semantics,
     - integrating sources into the DB schema.
     """
     source_table_name = 'SourceTable'
 
-    def __init__(self, dataset, **kw):
+    def __init__(self, dataset: Dataset, **kw):
         """
-        :param dataset: a `pycldf.Dataset` instance.
+        :param dataset: The :class:`Dataset` instance from which to derive the database schema.
         """
         self.dataset = dataset
         self._retranslate = collections.defaultdict(dict)
@@ -269,9 +270,9 @@ def retranslate(self, table, item):
     @staticmethod
     def round_geocoordinates(item, precision=4):
         """
-        We round geo coordinates to `precision` decimal places.
+        We round geo coordinates to ``precision`` decimal places.
 
-        See https://en.wikipedia.org/wiki/Decimal_degrees
+        .. seealso:: `<https://en.wikipedia.org/wiki/Decimal_degrees>`_
 
         :param item:
         :param precision:
diff --git a/src/pycldf/media.py b/src/pycldf/media.py
index f0e9310..9c85be7 100644
--- a/src/pycldf/media.py
+++ b/src/pycldf/media.py
@@ -1,7 +1,8 @@
 """
 Accessing media associated with a CLDF dataset.
 
-You can iterate over the `File` objects associated with media using the `Media` wrapper:
+You can iterate over the :class:`.File` objects associated with media using the :class:`.Media`
+wrapper:
 
 .. code-block:: python
 
@@ -11,7 +12,7 @@
         if f.mimetype.type == 'audio':
             f.save(directory)
 
-or instantiate a `File` from a `pycldf.orm.Object`:
+or instantiate a :class:`.File` from a :class:`pycldf.orm.Object`:
 
 .. code-block:: python
 
@@ -21,6 +22,7 @@
 
 """
 import io
+import json
 import base64
 import typing
 import logging
@@ -28,6 +30,7 @@
 import zipfile
 import functools
 import mimetypes
+import collections
 import urllib.parse
 import urllib.request
 
@@ -71,7 +74,7 @@ def __init__(self, media: 'MediaTable', row: dict):
         if self.url:
             self.url = anyURI.to_string(self.url)
             self.parsed_url = urllib.parse.urlparse(self.url)
-            self.scheme = self.parsed_url.scheme
+            self.scheme = self.parsed_url.scheme or 'file'
 
     @classmethod
     def from_dataset(
@@ -127,10 +130,14 @@ def local_path(self, d: pathlib.Path) -> pathlib.Path:
         return d.joinpath('{}{}'.format(
             self.id, '.zip' if self.path_in_zip else (self.mimetype.extension or '')))
 
+    def read_json(self, d=None):
+        assert self.mimetype.subtype.endswith('json')
+        return json.loads(self.read(d=d))
+
     def read(self, d=None) -> typing.Union[None, str, bytes]:
         """
         :param d: A local directory where the file has been saved before. If `None`, the content \
-        will read from the file's URL.
+        will be read from the file's URL.
         """
         if self.path_in_zip:
             zipcontent = None
@@ -148,7 +155,7 @@ def read(self, d=None) -> typing.Union[None, str, bytes]:
             return self.mimetype.read(self.local_path(d).read_bytes())
         if self.url:
             try:
-                return self.url_reader[self.scheme or 'file'](self.parsed_url, self.mimetype)
+                return self.url_reader[self.scheme](self.parsed_url, self.mimetype)
             except KeyError:
                 raise ValueError('Unsupported URL scheme: {}'.format(self.scheme))
 
@@ -206,13 +213,20 @@ def __iter__(self) -> typing.Generator[File, None, None]:
             yield File(self, row)
 
     def validate(self, success: bool = True, log: logging.Logger = None) -> bool:
+        speaker_area_files = collections.defaultdict(list)
+        if ('LanguageTable', 'speakerArea') in self.ds:
+            for lg in self.ds.iter_rows('LanguageTable', 'id', 'speakerArea'):
+                if lg['speakerArea']:
+                    speaker_area_files[lg['speakerArea']].append(lg['id'])
+
         for file in self:
+            content = None
             if not file.url:
                 success = False
                 log_or_raise('File without URL: {}'.format(file.id), log=log)
             elif file.scheme == 'file':
                 try:
-                    file.read()
+                    content = file.read()
                 except FileNotFoundError:
                     success = False
                     log_or_raise('Non-existing local file referenced: {}'.format(file.id), log=log)
@@ -221,10 +235,22 @@ def validate(self, success: bool = True, log: logging.Logger = None) -> bool:
                     log_or_raise('Error reading {}: {}'.format(file.id, e), log=log)
             elif file.scheme == 'data':
                 try:
-                    file.read()
+                    content = file.read()
                 except Exception as e:  # pragma: no cover
                     success = False
                     log_or_raise('Error reading {}: {}'.format(file.id, e), log=log)
+            if file.id in speaker_area_files and file.mimetype.subtype == 'geo+json' and content:
+                content = json.loads(content)
+                if content['type'] != 'Feature':
+                    assert content['type'] == 'FeatureCollection'
+                    for feature in content['features']:
+                        lid = feature['properties'].get('cldf:languageReference')
+                        if lid and lid in speaker_area_files[file.id]:
+                            speaker_area_files[file.id].remove(lid)
+                    if speaker_area_files[file.id]:
+                        log_or_raise(
+                            'Error: Not all language IDs found in speakerArea GeoJSON: {}'.format(
+                                speaker_area_files[file.id]))  # pragma: no cover
 
         return success
 
diff --git a/src/pycldf/modules/TextCorpus-metadata.json b/src/pycldf/modules/TextCorpus-metadata.json
new file mode 100644
index 0000000..9ab0342
--- /dev/null
+++ b/src/pycldf/modules/TextCorpus-metadata.json
@@ -0,0 +1,97 @@
+{
+    "@context": [
+        "http://www.w3.org/ns/csvw",
+        {
+            "@language": "en"
+        }
+    ],
+    "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#TextCorpus",
+    "dialect": {
+        "commentPrefix": null
+    },
+    "tables": [
+        {
+            "url": "examples.csv",
+            "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#ExampleTable",
+            "tableSchema": {
+                "columns": [
+                    {
+                        "name": "ID",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+                        "datatype": {
+                            "base": "string",
+                            "format": "[a-zA-Z0-9_\\-]+"
+                        }
+                    },
+                    {
+                        "name": "Language_ID",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#languageReference",
+                        "dc:extent": "singlevalued",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Primary_Text",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#primaryText",
+                        "dc:description": "The example text in the source language.",
+                        "dc:extent": "singlevalued",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Analyzed_Word",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#analyzedWord",
+                        "dc:description": "The sequence of words of the primary text to be aligned with glosses",
+                        "dc:extent": "multivalued",
+                        "datatype": "string",
+                        "separator": "\t"
+                    },
+                    {
+                        "name": "Gloss",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#gloss",
+                        "dc:description": "The sequence of glosses aligned with the words of the primary text",
+                        "dc:extent": "multivalued",
+                        "datatype": "string",
+                        "separator": "\t"
+                    },
+                    {
+                        "name": "Translated_Text",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#translatedText",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "The translation of the example text in a meta language",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Meta_Language_ID",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#metaLanguageReference",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "References the language of the translated text",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "LGR_Conformance",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#lgrConformance",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "The level of conformance of the example with the Leipzig Glossing Rules",
+                        "datatype": {
+                            "base": "string",
+                            "format": "WORD_ALIGNED|MORPHEME_ALIGNED"
+                        }
+                    },
+                    {
+                        "name": "Comment",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#comment",
+                        "datatype": "string"
+                    }
+                ]
+            }
+        }
+    ]
+}
\ No newline at end of file
diff --git a/src/pycldf/orm.py b/src/pycldf/orm.py
index 110ecd4..be4cabd 100644
--- a/src/pycldf/orm.py
+++ b/src/pycldf/orm.py
@@ -1,10 +1,10 @@
 """
 Object oriented (read-only) access to CLDF data
 
-To read ORM objects from a `pycldf.Dataset`, use two methods
+To read ORM objects from a `pycldf.Dataset`, there are two generic methods:
 
-* `pycldf.Dataset.objects`
-* `pycldf.Dataset.get_object`
+* :meth:`pycldf.Dataset.objects`
+* :meth:`pycldf.Dataset.get_object`
 
 Both will return default implementations of the objects, i.e. instances of the corresponding
 class defined in this module. To customize these objects,
@@ -25,6 +25,11 @@ def custom_method(self):
 
 2. pass the class into the `objects` or `get_object` method.
 
+In addition, module-specific subclasses of :class:`pycldf.Dataset` provide more meaningful
+properties and methods, as shortcuts to the methods above. See
+`<./dataset.html#subclasses-supporting-specific-cldf-modules>`_ for details.
+
+
 Limitations:
 ------------
 * We only support foreign key constraints for CLDF reference properties targeting either a \
@@ -37,8 +42,8 @@ def custom_method(self):
   Reading ~400,000 rows from a ValueTable of a StructureDataset takes
 
   * ~2secs with csvcut, i.e. only making sure it's valid CSV
-  * ~15secs iterating over pycldf.Dataset['ValueTable']
-  * ~35secs iterating over pycldf.Dataset.objects('ValueTable')
+  * ~15secs iterating over ``pycldf.Dataset['ValueTable']``
+  * ~35secs iterating over ``pycldf.Dataset.objects('ValueTable')``
 """
 import types
 import typing
@@ -52,6 +57,9 @@ def custom_method(self):
 from pycldf.util import DictTuple
 from pycldf.sources import Reference
 
+if typing.TYPE_CHECKING:
+    from pycldf import Dataset  # pragma: no cover
+
 
 class Object:
     """
@@ -71,7 +79,7 @@ class Object:
     # specified here:
     __component__ = None
 
-    def __init__(self, dataset, row: dict):
+    def __init__(self, dataset: 'Dataset', row: dict):
         # Get a mapping of column names to pairs (CLDF property name, list-valued) for columns
         # present in the component specified by class name.
         cldf_cols = {
@@ -113,7 +121,7 @@ def component(self) -> str:
         return self.__class__.component_name()
 
     @property
-    def key(self):
+    def key(self) -> typing.Tuple[int, str, str]:
         return id(self.dataset), self.__class__.__name__, self.id
 
     def __hash__(self):
@@ -141,13 +149,13 @@ def aboutUrl(self, col='id') -> typing.Union[str, None]:
         """
         return self._expand_uritemplate('aboutUrl', col)
 
-    def valueUrl(self, col='id'):
+    def valueUrl(self, col='id') -> typing.Union[str, None]:
         """
         The table's `valueUrl` property, expanded with the object's row as context.
         """
         return self._expand_uritemplate('valueUrl', col)
 
-    def propertyUrl(self, col='id'):
+    def propertyUrl(self, col='id') -> typing.Union[str, None]:
         """
         The table's `propertyUrl` property, expanded with the object's row as context.
         """
@@ -168,7 +176,7 @@ def references(self) -> typing.Tuple[Reference]:
             multi=True,
         )
 
-    def related(self, relation: str):
+    def related(self, relation: str) -> typing.Union[None, 'Object']:
         """
         The CLDF ontology specifies several "reference properties". This method returns the first
         related object specified by such a property.
@@ -253,6 +261,22 @@ def cognateset(self):
         return self.related('cognatesetReference')
 
 
+class Contribution(Object):
+    @property
+    def sentences(self):
+        res = []
+        if self.dataset.module == 'TextCorpus':
+            # Return the list of lines, ordered by position.
+            for e in self.dataset.objects('ExampleTable'):
+                if e.cldf.contributionReference == self.id:
+                    if not getattr(e.cldf, 'exampleReference', None):
+                        # Not just an alternative translation line.
+                        res.append(e)
+        if res and hasattr(res[0].cldf, 'position'):
+            return sorted(res, key=lambda e: getattr(e.cldf, 'position'))
+        return res
+
+
 class Entry(Object, _WithLanguageMixin):
     @property
     def senses(self):
@@ -272,6 +296,25 @@ def igt(self):
             self.cldf.translatedText,
         )
 
+    @property
+    def text(self):
+        """
+        Examples in a TextCorpus are interpreted as lines of text.
+        """
+        if self.dataset.module == 'TextCorpus' and hasattr(self.cldf, 'contributionReference'):
+            return self.related('contributionReference')
+
+    @property
+    def alternative_translations(self):
+        res = []
+        if hasattr(self.cldf, 'exampleReference'):
+            # There's a self-referential foreign key. We assume this to link together full examples
+            # and alternative translations.
+            for ex in self.dataset.objects('ExampleTable'):
+                if ex.cldf.exampleReference == self.id:
+                    res.append(ex)
+        return res
+
 
 class Form(Object, _WithLanguageMixin, _WithParameterMixin):
     pass
@@ -288,6 +331,9 @@ def form(self):  # pragma: no cover
 
 
 class Language(Object):
+    """
+    FIXME: describe usage!
+    """
     @property
     def lonlat(self):
         """
@@ -305,6 +351,25 @@ def as_geojson_feature(self):
                 "properties": self.cldf,
             }
 
+    @functools.cached_property
+    def speaker_area(self):
+        from pycldf.media import File
+
+        if getattr(self.cldf, 'speakerArea', None):
+            return File.from_dataset(self.dataset, self.related('speakerArea'))
+
+    @functools.cached_property
+    def speaker_area_as_geojson_feature(self):
+        if self.speaker_area and self.speaker_area.mimetype.subtype == 'geo+json':
+            res = self.speaker_area.read_json()
+            if res['type'] == 'FeatureCollection':
+                for feature in res['features']:
+                    if feature['properties']['cldf:languageReference'] == self.id:
+                        return feature
+            else:
+                assert res['type'] == 'Feature'
+                return res
+
     @property
     def values(self):
         return DictTuple(v for v in self.dataset.objects('ValueTable') if self in v.languages)
@@ -326,6 +391,18 @@ def glottolog_languoid(self, glottolog_api):
         return glottolog_api.languoid(self.cldf.glottocode)
 
 
+class Media(Object):
+    @property
+    def downloadUrl(self):
+        if hasattr(self.cldf, 'downloadUrl'):
+            return self.cldf.downloadUrl
+        return self.valueUrl()
+
+
+class ParameterNetworkEdge(Object):
+    __component__ = 'ParameterNetwork'
+
+
 class Parameter(Object):
     @functools.cached_property
     def columnSpec(self):
@@ -375,6 +452,10 @@ def entries(self):
         return self.all_related('entryReference')
 
 
+class Tree(Object):
+    pass
+
+
 class Value(Object, _WithLanguageMixin, _WithParameterMixin):
     """
     Value objects correspond to rows in a dataset's ``ValueTable``.
@@ -420,15 +501,3 @@ def code(self):
     @property
     def examples(self):
         return self.all_related('exampleReference')
-
-
-class Contribution(Object):
-    pass
-
-
-class Media(Object):
-    @property
-    def downloadUrl(self):
-        if hasattr(self.cldf, 'downloadUrl'):
-            return self.cldf.downloadUrl
-        return self.valueUrl()
diff --git a/src/pycldf/terms.rdf b/src/pycldf/terms.rdf
index d864c9f..0ad63ed 100644
--- a/src/pycldf/terms.rdf
+++ b/src/pycldf/terms.rdf
@@ -82,6 +82,25 @@
         <rdfs:subPropertyOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#comment" />
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#position" dc:type="generic-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                A position represents the placement of an item in a series or sequence of items.
+                Although an integer is the recommended datatype, any datatype that supports a total
+                ordering (where the order is transparent, such as alphabetic order for strings) is
+                acceptable. It is also possible to have a list-valued column for this property,
+                which can be useful for implementing multi-level orderings. In such cases, the
+                typical order for tuples is assumed.
+            </p>
+        </rdfs:comment>
+        <csvw:name>"Position"</csvw:name>
+        <csvw:separator>";"</csvw:separator>
+        <csvw:datatype>{"base": "string"}</csvw:datatype>
+        <rdfs:subPropertyOf rdf:resource="https://www.wikidata.org/wiki/Property:P1545" />
+        <rdfs:subPropertyOf rdf:resource="https://schema.org/position" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <!--
         Reference properties (aka foreign keys)
     -->
@@ -92,7 +111,7 @@
                 An identifier referencing a language either
             </p>
             <ul>
-                <li>by providing a foreign key into the LanguageTable or</li>
+                <li>by providing a foreign key to <code>LanguageTable</code> or</li>
                 <li>by using a known encoding scheme.</li>
             </ul>
         </rdfs:comment>
@@ -110,7 +129,7 @@
                 an example - either
             </p>
             <ul>
-                <li>by providing a foreign key into the LanguageTable or</li>
+                <li>by providing a foreign key to <code>LanguageTable</code> or</li>
                 <li>by using a known encoding scheme.</li>
             </ul>
         </rdfs:comment>
@@ -127,7 +146,7 @@
                 An identifier referencing a parameter either
             </p>
             <ul>
-                <li>by providing a foreign key into the ParameterTable or</li>
+                <li>by providing a foreign key to <code>ParameterTable</code> or</li>
                 <li>by using a known encoding scheme.</li>
             </ul>
         </rdfs:comment>
@@ -142,7 +161,7 @@
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing a code (aka category) description
-                by providing a foreign key into the CodeTable.
+                by providing a foreign key to <code>CodeTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#CodeTable"/>
@@ -155,8 +174,8 @@
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
-                An identifier referencing an example by providing a foreign key into the
-                ExampleTable.
+                An identifier referencing an example by providing a foreign key to
+                <code>ExampleTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#ExampleTable"/>
@@ -170,8 +189,7 @@
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
-                An identifier referencing a dictionary entry
-                by providing a foreign key into the EntryTable.
+                An identifier referencing a dictionary entry by providing a foreign key to <code>EntryTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#EntryTable"/>
@@ -186,7 +204,7 @@
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing a form
-                by providing a foreign key into the FormTable.
+                by providing a foreign key to <code>FormTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#FormTable"/>
@@ -200,7 +218,7 @@
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing the source form of a loanword
-                by providing a foreign key into the FormTable.
+                by providing a foreign key to <code>FormTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#FormTable"/>
@@ -214,7 +232,7 @@
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing a loanword
-                by providing a foreign key into the FormTable.
+                by providing a foreign key to <code>FormTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#FormTable"/>
@@ -223,6 +241,34 @@
         <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Foreign_key" />
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#sourceParameterReference"
+                  dc:type="reference-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier referencing the source parameter of a parameter network edge.
+            </p>
+        </rdfs:comment>
+        <dc:references rdf:resource="#Parameter"/>
+        <csvw:name>"Source_Parameter_ID"</csvw:name>
+        <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/references" />
+        <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Foreign_key" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#targetParameterReference"
+                  dc:type="reference-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier referencing the target parameter of a parameter network edge.
+            </p>
+        </rdfs:comment>
+        <dc:references rdf:resource="#Parameter"/>
+        <csvw:name>"Target_Parameter_ID"</csvw:name>
+        <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/references" />
+        <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Foreign_key" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#cognatesetReference"
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
@@ -230,7 +276,7 @@
                 An identifier referencing a cognateset either
             </p>
             <ul>
-                <li>by providing a foreign key into the CognatesetTable or</li>
+                <li>by providing a foreign key to <code>CognatesetTable</code> or</li>
                 <li>by using a known encoding scheme.</li>
             </ul>
         </rdfs:comment>
@@ -240,12 +286,26 @@
         <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Foreign_key" />
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#treeReference"
+                  dc:type="reference-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier referencing a language tree by providing a foreign key <code>TreeTable</code>.
+            </p>
+        </rdfs:comment>
+        <dc:references rdf:resource="#TreeTable"/>
+        <csvw:name>"Tree_ID"</csvw:name>
+        <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/references" />
+        <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Foreign_key" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#mediaReference"
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing a media resource
-                by providing a foreign key into the MediaTable
+                by providing a foreign key to <code>MediaTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#MediaTable"/>
@@ -255,12 +315,41 @@
         <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.1"/>
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#speakerArea"
+                  dc:type="reference-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier referencing a media resource
+                by providing a foreign key to <code>MediaTable</code>.
+            </p>
+            <p>
+                This property can be used in <code>LanguageTable</code> to point to a media resource describing
+                the speaker area of a language, i.e. the geographic area where the speakers of the
+                language live.
+            </p>
+            <p>
+                The linked media resource may be an image of a map, depicting the area, or some other
+                multimedia content for human consumption. But it may also be a GeoJSON
+                resource (i.e. a media resource with <code>mediaType</code> <code>application/geo+json</code>).
+                In the latter case, the GeoJSON object MUST contain a feature with a geometry of type
+                <code>Polygon</code> or <code>Multipolygon</code> and a key <code>cldf:languageReference</code>
+                in its <code>properties</code> object with the linking language's <code>id</code> as
+                value.
+            </p>
+        </rdfs:comment>
+        <dc:references rdf:resource="#MediaTable"/>
+        <csvw:name>"Media_ID"</csvw:name>
+        <rdfs:subPropertyOf rdf:resource="http://cldf.clld.org/v1.0/terms.rdf#mediaReference" />
+        <rdfs:seeAlso rdf:resource="https://datatracker.ietf.org/doc/html/rfc7946" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#contributionReference"
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 An identifier referencing a contribution
-                by providing a foreign key into the ContributionTable
+                by providing a foreign key to <code>ContributionTable</code>.
             </p>
         </rdfs:comment>
         <dc:references rdf:resource="#ContributionTable"/>
@@ -276,7 +365,7 @@
             <p> A functional equivalent set is a group of strings from different languages that express similar function.
                 This is an identifier referencing a cognateset either
                 <ul>
-                    <li>by providing a foreign key into the FunctionalEquivalentsetTable or</li>
+                    <li>by providing a foreign key to <code>FunctionalEquivalentsetTable</code> or</li>
                     <li>by using a known encoding scheme.</li>
                 </ul>
             </p>
@@ -289,11 +378,16 @@
 
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#concepticonReference"
                   dc:type="reference-property">
-        <rdfs:comment>
-            A concept set groups a number of concept labels which are used in
-            different questionnaires and were judged to denote the same concept despite
-            potential differences among the concrete concept labels (be it their spelling,
-            or the language in which they were originally created).
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier of a Concepticon concept set.
+            </p>
+            <p>
+                A concept set groups a number of concept labels which are used in
+                different questionnaires and were judged to denote the same concept despite
+                potential differences among the concrete concept labels (be it their spelling,
+                or the language in which they were originally created).
+            </p>
         </rdfs:comment>
         <csvw:name>"Concepticon_ID"</csvw:name>
         <csvw:datatype>{"base": "string", "format": "[0-9]+"}</csvw:datatype>
@@ -306,6 +400,14 @@
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#cltsReference"
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
+            <p>
+                An identifier of a sound described in the CLTS dataset.
+            </p>
+            <p>
+                A sound identifier is the last path component of the sound's URL at
+                https://clts.clld.org/parameters , e.g. <code>short_neutral_tone</code> for
+                <code>https://clts.clld.org/parameters/short_neutral_tone</code>.
+            </p>
             <p>
                 References a sound in the Cross-Linguistic Transcription Systems database. Suitable to
                 mark parameters as phonemes, and consequently values as elements of phoneme inventories.
@@ -328,8 +430,11 @@
                   dc:type="reference-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
-                References a taxonomic unit in GBIF's Backbone Taxonomy. Can be used in for example in a
-                ParameterTable to mark a lexical concept as biological species. E.g.
+                A numeric identifier for a unit in GBIF's Backbone Taxonomy.
+            </p>
+            <p>
+                References a taxonomic unit in GBIF's Backbone Taxonomy. Can be used for example in
+                <code>ParameterTable</code> to mark a lexical concept as biological species. E.g.
                 <a href="https://www.gbif.org/species/5219404">5219404</a>.
             </p>
         </rdfs:comment>
@@ -356,18 +461,32 @@
 
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#glottocode" dc:type="language-property">
         <rdfs:comment rdf:parseType="Literal">
-            <p>A <a href="http://glottolog.org">Glottolog</a> code denoting a languoid.</p>
+            <p>A Glottocode denoting a languoid described in <a href="http://glottolog.org">Glottolog</a>.</p>
         </rdfs:comment>
         <csvw:name>"Glottocode"</csvw:name>
         <csvw:datatype>{"base": "string", "format": "[a-z0-9]{4}[1-9][0-9]{3}"}</csvw:datatype>
         <csvw:valueUrl>"http://glottolog.org/resource/languoid/id/{Glottocode}"</csvw:valueUrl>
-        <rdfs:seeAlso rdf:resource="http://glottolog.org" />
+        <rdfs:seeAlso rdf:resource="https://content.iospress.com/articles/semantic-web/sw212843" />
         <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/identifier" />
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#parentLanguageGlottocode" dc:type="language-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                A <a href="http://glottolog.org">Glottocode</a> denoting the language-level languoid that is
+                a parent languoid of the languoid described by the row in <code>LanguageTable</code>.
+            </p>
+        </rdfs:comment>
+        <csvw:name>"Parent_Language_Glottocode"</csvw:name>
+        <csvw:datatype>{"base": "string", "format": "[a-z0-9]{4}[1-9][0-9]{3}"}</csvw:datatype>
+        <csvw:valueUrl>"http://glottolog.org/resource/languoid/id/{Glottocode}"</csvw:valueUrl>
+        <rdfs:seeAlso rdf:resource="https://glottolog.org/glottolog/glottologinformation" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#macroarea" dc:type="language-property">
         <rdfs:comment rdf:parseType="Literal">
-            <p>A macroarea as defined by <a href="http://glottolog.org">Glottolog</a>.</p>
+            <p>The name of a macroarea as defined by <a href="http://glottolog.org">Glottolog</a>.</p>
         </rdfs:comment>
         <csvw:name>"Macroarea"</csvw:name>
         <rdfs:seeAlso rdf:resource="http://glottolog.org/meta/glossary#macroarea" />
@@ -408,7 +527,7 @@
                 <a href="https://www.w3.org/TR/tabular-metadata/#columns">CSVW column description</a>.
                 This column specification may be used by CLDF consumers to read a parameter's value as typed data.</p>
             <p>Note that a CSVW datatye description is not sufficient, because parsing a string value
-                must also be informed by the column properties "null" and "separator".</p>
+                must also be informed by the column properties <code>null</code> and <code>separator</code>.</p>
         </rdfs:comment>
         <csvw:name>"ColumnSpec"</csvw:name>
         <csvw:datatype>{"base": "json"}</csvw:datatype>
@@ -422,7 +541,7 @@
     -->
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#contributor" dc:type="contribution-property">
         <rdfs:comment rdf:parseType="Literal">
-            <p>Contributor(s) to a citeable unit of a dataset.</p>
+            <p>Names of contributor(s) to a citeable unit of a dataset.</p>
         </rdfs:comment>
         <csvw:name>"Contributor"</csvw:name>
         <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/creator" />
@@ -443,15 +562,28 @@
         <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.1"/>
     </rdf:Property>
 
+    <!--
+        Parameter network properties
+    -->
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#edgeIsDirected" dc:type="network-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>Flag signaling whether an edge in a graph is directed or not.</p>
+        </rdfs:comment>
+        <csvw:name>"Edge_Is_Directed"</csvw:name>
+        <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Mixed_graph" />
+        <csvw:datatype>{"base": "boolean", "format": "Yes|No"}</csvw:datatype>
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <!--
         Tree properties
     -->
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#treeType" dc:type="tree-property">
         <rdfs:comment rdf:parseType="Literal">
-            <p>The type of a tree ("summary" or "sample") describes how the tree can be used.
-                Summary (or consensus) trees can be analysed in isolation and should have type "summary".
+            <p>The type of a tree (<code>summary</code> or <code>sample</code>) describes how the tree can be used.
+                Summary (or consensus) trees can be analysed in isolation and should have type <code>summary</code>.
                 Trees resulting from a method that creates multiple trees, and thus should be analysed as a whole
-                (or sampled appropriately) should have type "sample".</p>
+                (or sampled appropriately) should have type <code>sample</code>.</p>
         </rdfs:comment>
         <csvw:name>"Tree_Type"</csvw:name>
         <csvw:datatype>{"base": "string", "format": "summary|sample"}</csvw:datatype>
@@ -460,7 +592,7 @@
 
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#treeIsRooted" dc:type="tree-property">
         <rdfs:comment rdf:parseType="Literal">
-            <p>Whether a tree is rooted or not.</p>
+            <p>Flag signaling whether a tree is rooted or not.</p>
         </rdfs:comment>
         <csvw:name>"Tree_Is_Rooted"</csvw:name>
         <rdfs:seeAlso rdf:resource="https://en.wikipedia.org/wiki/Tree_(graph_theory)#Rooted_tree" />
@@ -563,6 +695,56 @@
         <rdfs:subPropertyOf rdf:resource="http://purl.org/linguistics/gold/hasTranslationLine" />
     </rdf:Property>
 
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#lgrConformance" dc:type="example-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                The level of conformance of the example with the Leipzig Glossing Rules.
+            </p>
+            <p>
+                The following levels are distinguished:
+            </p>
+            <ol>
+                <li><code>WORD_ALIGNED</code>: Analyzed text and glosses obey LGR rule 1, "word-by-word alignment".</li>
+                <li><code>MORPHEME_ALIGNED</code>: Analyzed text and glosses obey LGR rule 2, "morpheme-by-morpheme correspondence".</li>
+            </ol>
+            <p>
+                No information regarding LGR conformance should be signaled with an empty string, i.e.
+                <code>null</code> value for the property.
+            </p>
+            <p>
+                While more information is needed to assess how to interpret IGT - e.g. whether rule 4a is
+                followed to group gloss elements for unsegmentable morpheme - the two levels considered here
+                are essential for decisions about automated re-use.
+            </p>
+        </rdfs:comment>
+        <rdfs:seeAlso rdf:resource="https://doi.org/10.5281/zenodo.10275705" />
+        <csvw:name>"LGR_Conformance"</csvw:name>
+        <csvw:datatype>{"base": "string", "format": "WORD_ALIGNED|MORPHEME_ALIGNED"}</csvw:datatype>
+        <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/terms/conformsTo" />
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
+    <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#grammaticalityJudgement" dc:type="example-property">
+        <rdfs:comment rdf:parseType="Literal">
+            <p>
+                A judgement about the (un)grammaticality of the example.
+            </p>
+            <p>
+                A non-<code>null</code> value for this property flags an example as ungrammatical
+                or unacceptable. The actual string value is the typographical symbol(s) or text which is to be
+                used to mark the example when formatting it in text (e.g. <code>*</code>).
+            </p>
+            <p>
+                <strong>Note:</strong> Ungrammatical examples should link (via <code>languageReference</code>)
+                to special item(s) in <code>LanguageTable</code> with an empty <code>Glottocode</code> to
+                prevent data aggregators from inadvertently assigning such an example to a proper language
+                (if they fail to honour <code>grammaticalityJudgement</code>).
+            </p>
+        </rdfs:comment>
+        <csvw:name>"Grammaticality_Judgement"</csvw:name>
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdf:Property>
+
     <!--
         Dictionary entry properties
     -->
@@ -579,13 +761,13 @@
     <rdf:Property rdf:about="http://cldf.clld.org/v1.0/terms.rdf#partOfSpeech" dc:type="entry-property">
         <rdfs:comment rdf:parseType="Literal">
             <p>
-                The part-of-speech of dictionary entry.
+                The part-of-speech of a dictionary entry.
             </p>
         </rdfs:comment>
         <csvw:name>"Part_Of_Speech"</csvw:name>
         <rdfs:subPropertyOf rdf:resource="http://purl.org/linguistics/gold/PartOfSpeechProperty" />
     </rdf:Property>
-    
+
     <!--
         Value properties
     -->
@@ -597,8 +779,8 @@
             </p>
             <p>
                 For features with a limited, discrete set of valid values (a.k.a. categorical variables)
-                it is recommended to relate items of a ValueTable to the respective code
-                in the CodeTable.
+                it is recommended to relate items of <code>ValueTable</code> to the respective code
+                in <code>CodeTable</code>.
             </p>
         </rdfs:comment>
         <csvw:name>"Value"</csvw:name>
@@ -734,7 +916,7 @@
         <rdfs:comment rdf:parseType="Literal">
             <p>
                 A generic CLDF dataset; i.e. a set of cross-linguistic data which does
-                not fit any of the established CLDF modules.
+                not fit any of the other CLDF modules.
             </p>
         </rdfs:comment>
         <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/dcat#Distribution"/>
@@ -780,13 +962,24 @@
         <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/dcat#Distribution"/>
     </rdfs:Class>
 
+    <rdfs:Class rdf:about="http://cldf.clld.org/v1.0/terms.rdf#TextCorpus" dc:type="module">
+        <csvw:name xml:lang="en">"TextCorpus"</csvw:name>
+        <rdfs:comment rdf:parseType="Literal">
+            <p>A dataset according to the
+                <a href="https://github.com/cldf/cldf/tree/master/modules/TextCorpus">CLDF Text Corpus</a>
+                specification</p>
+        </rdfs:comment>
+        <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/dcat#Distribution"/>
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
+    </rdfs:Class>
+
     <!--
         CLDF components
     -->
     <rdfs:Class rdf:about="http://cldf.clld.org/v1.0/terms.rdf#ValueTable" dc:type="table">
         <csvw:name xml:lang="en">"ValueTable"</csvw:name>
         <rdfs:comment>
-            The table of value assignments of a CLDF Structure Dataset
+            The table of value assignments of a <code>Structure Dataset</code>
         </rdfs:comment>
         <csvw:url>"values.csv"</csvw:url>
     </rdfs:Class>
@@ -804,7 +997,7 @@
     <rdfs:Class rdf:about="http://cldf.clld.org/v1.0/terms.rdf#ExampleTable" dc:type="table">
         <csvw:name xml:lang="en">"ExampleTable"</csvw:name>
         <rdfs:comment>
-            The table of examples provided with a CLDF dataset
+            The table of text examples provided with a CLDF dataset
         </rdfs:comment>
         <csvw:url>"examples.csv"</csvw:url>
     </rdfs:Class>
@@ -931,6 +1124,16 @@
             as tree structure with items of the LanguageTable as leaf nodes.
         </rdfs:comment>
         <csvw:url>"trees.csv"</csvw:url>
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.2"/>
+    </rdfs:Class>
+
+    <rdfs:Class rdf:about="http://cldf.clld.org/v1.0/terms.rdf#ParameterNetwork" dc:type="table">
+        <csvw:name xml:lang="en">"ParameterNetwork"</csvw:name>
+        <rdfs:comment>
+            A table listing edges of a parameter network, i.e. a graph with parameters as nodes.
+        </rdfs:comment>
+        <csvw:url>"parameter_network.csv"</csvw:url>
+        <dc:hasVersion rdf:resource="http://cldf.clld.org/v1.3"/>
     </rdfs:Class>
 
 </rdf:RDF>
diff --git a/src/pycldf/validators.py b/src/pycldf/validators.py
index c85444b..80cffd8 100644
--- a/src/pycldf/validators.py
+++ b/src/pycldf/validators.py
@@ -28,6 +28,15 @@ def valid_igt(dataset, table, column, row):
         raise ValueError('number of words and word glosses does not match')
 
 
+def valid_grammaticalityJudgement(dataset, table, column, row):
+    lid_name = dataset.readonly_column_names.ExampleTable.languageReference[0]
+    gc_name = dataset.readonly_column_names.LanguageTable.glottocode[0]
+    if row[column.name] is not None:
+        lg = dataset.get_row('LanguageTable', row[lid_name])
+        if lg[gc_name]:
+            raise ValueError('Glottolog language linked from ungrammatical example')
+
+
 VALIDATORS = [
     (
         None,
@@ -44,5 +53,9 @@ def valid_igt(dataset, table, column, row):
     (
         None,
         'http://cldf.clld.org/v1.0/terms.rdf#source',
-        valid_references)
+        valid_references),
+    (
+        None,
+        'http://cldf.clld.org/v1.0/terms.rdf#grammaticalityJudgement',
+        valid_grammaticalityJudgement),
 ]
diff --git a/tests/conftest.py b/tests/conftest.py
index 17811c1..2ee225b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -57,11 +57,22 @@ def dictionary(data):
     return Dataset.from_metadata(data / 'dictionary' / 'metadata.json')
 
 
+@pytest.fixture(scope='module')
+def textcorpus(data):
+    return Dataset.from_metadata(data / 'textcorpus' / 'metadata.json')
+
+
 @pytest.fixture(scope='module')
 def structuredataset_with_examples(data):
     return Dataset.from_metadata(data / 'structuredataset_with_examples' / 'metadata.json')
 
 
+@pytest.fixture
+def dataset_with_media(data):
+    dsdir = data / 'dataset_with_media'
+    return Dataset.from_metadata(dsdir / 'metadata.json')
+
+
 @pytest.fixture(scope='module')
 def wordlist_with_borrowings(data):
     return Dataset.from_metadata(data / 'wordlist_with_borrowings' / 'metadata.json')
diff --git a/tests/data/dataset_with_media/erzya.geojson b/tests/data/dataset_with_media/erzya.geojson
new file mode 100644
index 0000000..9a6b631
--- /dev/null
+++ b/tests/data/dataset_with_media/erzya.geojson
@@ -0,0 +1,33 @@
+{
+    "id": 72, 
+    "type": "Feature", 
+    "properties": {"Branch": "Mordvin", "Glottocode": "erzy1239", "ISO_639_3": "myv", "Sources": "Ermu\u0161kin 1984, Feoktistov 1990", "Timeperiod": "traditional", "Language": "Erzya", "Dialect": ""}, 
+    "geometry": {
+        "type": "MultiPolygon", 
+        "coordinates": [
+            [[[42.62555948081459, 54.688448862774045], [42.62413340244894, 54.701635598037065], [42.58551044671131, 54.7207212976511], [42.521336920254946, 54.728956953718765], [42.4314939832161, 54.745423245895836], [42.3459292812743, 54.77422315505452], [42.32881634088591, 54.80300257682697], [42.31740771396039, 54.85885834065671], [42.3459292812743, 54.834225617964435], [42.380155162051004, 54.84654385911282], [42.41321303273674, 54.837247777224704], [42.448606923604416, 54.84490164419394], [42.477330225489844, 54.84012749479537], [42.525733995215866, 54.842301333877195], [42.57136850291816, 54.82751743914127], [42.62413340244894, 54.824231393848926], [42.64552457793444, 54.83655268487905], [42.69971555583086, 54.82998179762], [42.77529770921275, 54.83408872749744], [42.81237574672085, 54.833267374946516], [42.83376692220636, 54.81683681415517], [42.86086241115455, 54.79628921051109], [42.90079260539405, 54.78724495454134], [42.92360985924523, 54.77244089848784], [42.92931417270797, 54.76503683846403], [42.917905545782375, 54.72717270358116], [42.89794044866266, 54.68267831839815], [42.853732019326074, 54.62988100747758], [42.80952358998946, 54.59519548030617], [42.732515358241855, 54.5604803864136], [42.678324380345366, 54.54642063031613], [42.65693320485989, 54.55799960514113], [42.64124634283729, 54.58693266401557], [42.6298377159117, 54.62657889744592], [42.63126379427738, 54.65628823827317], [42.62555948081459, 54.688448862774045]]], 
+            [[[43.144913453628526, 54.18825965194049], [43.18912188296511, 54.178245249577344], [43.2190695286447, 54.17407186605909], [43.23475639066741, 54.15904419830698], [43.27611266327259, 54.13064370922123], [43.318895014243495, 54.0796410531189], [43.29892991712371, 54.057046075378814], [43.2704083498098, 54.049511683704694], [43.227625998838896, 54.061231258150436], [43.20480874498775, 54.06039425533075], [43.172008942576724, 54.05286047091207], [43.12922659160582, 54.05034890581001], [43.09927894592623, 54.05369762554198], [43.06220090841813, 54.06457910076081], [43.072183456977996, 54.0946975417204], [43.080739927172196, 54.12228691669576], [43.090722475732036, 54.152363482720666], [43.10070502429191, 54.172402394737084], [43.1149658079489, 54.18241821198793], [43.13350482670294, 54.18742521104704], [43.144913453628526, 54.18825965194049]]], 
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+}
diff --git a/tests/data/dataset_with_media/erzya2.geojson b/tests/data/dataset_with_media/erzya2.geojson
new file mode 100644
index 0000000..da22f86
--- /dev/null
+++ b/tests/data/dataset_with_media/erzya2.geojson
@@ -0,0 +1,40 @@
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+            [[[46.84021978667119, 53.096690923925735], [46.89666872198005, 53.04492428696752], [47.000653602812044, 53.08955439749843], [47.057102538120866, 53.10739349441831], [47.09869649045369, 53.114527062106], [47.14029044278653, 53.11274378112609], [47.17594240192895, 53.08777008095032], [47.199710374690554, 53.06456723323225], [47.16108741895296, 53.05742537972639], [47.13731944619129, 53.05742537972639], [47.11355147342972, 53.050282342190485], [47.1046384836441, 53.04135188009843], [47.101667487048935, 53.02527238534767], [47.101667487048935, 53.00561152660287], [47.101667487048935, 52.99667181111702], [47.14029044278653, 52.9752089408365], [47.14920343257214, 52.962684008134445], [47.09869649045369, 52.9304603710004], [46.99768260621688, 52.882079899643955], [46.96500164366965, 52.87849401153252], [46.869929752623236, 52.882079899643955], [46.8194228105048, 52.90179698414577], [46.80753882412398, 52.92866946509722], [46.82833580029041, 52.9752089408365], [46.837248790076025, 53.0038237315919], [46.8194228105048, 53.02527238534767], [46.79565483774319, 53.04849639779178], [46.77188686498156, 53.07349288520233], [46.79565483774319, 53.08063207495259], [46.84021978667119, 53.096690923925735]]],
+            [[[47.07778067442362, 54.54598380728752], [47.07778067442362, 54.57699186198983], [47.14611359611323, 54.589044182570056], [47.21741751439804, 54.554599521164114], [47.22038851099328, 54.5046030458759], [47.12531661994684, 54.457999546254726], [47.08669366420924, 54.50115275585485], [47.06886768463798, 54.523574434122104], [47.07778067442362, 54.54598380728752]]],
+            [[[47.12056302539448, 53.671671482417985], [47.126505018584886, 53.69630501641493], [47.14730199475136, 53.7174080069329], [47.182953953893744, 53.73850041493003], [47.248315878988144, 53.743771863697454], [47.313677804082616, 53.73147078794884], [47.30773581089221, 53.70158175628954], [47.263170861964205, 53.65934931146511], [47.197808936869734, 53.639978619682935], [47.14730199475136, 53.624123252280036], [47.09679505263291, 53.624123252280036], [47.09679505263291, 53.64350122555498], [47.12056302539448, 53.671671482417985]]],
+            [[[47.12828761654207, 53.92610690943748], [47.140171602922855, 53.89985756443028], [47.12531661994684, 53.88585116667325], [47.095606653994786, 53.882348833735186], [47.02727373230521, 53.89110411593832], [47.000534762948405, 53.966323866111715], [47.05401270166202, 53.982050381897864], [47.11343263356604, 53.95933239815573], [47.12828761654207, 53.92610690943748]]],
+            [[[47.71488118429858, 53.547440261412255], [47.72438837340322, 53.57849705576769], [47.75053314344099, 53.60247987223423], [47.79569229168806, 53.62926809111617], [47.82421385900201, 53.63913315049595], [47.9074017636676, 53.630677526543494], [47.988212871057094, 53.60247987223423], [48.026241627475684, 53.57849705576769], [48.01673443837104, 53.54602804711638], [47.99058966833323, 53.51070737355606], [47.94780731736237, 53.47394261989025], [47.94543052008616, 53.39748318063712], [47.94780731736237, 53.31662668981753], [47.94543052008616, 53.2612154107886], [47.92403934460073, 53.23846178514429], [47.874126601801386, 53.22281164752865], [47.847981831763576, 53.22281164752865], [47.83847464265892, 53.228503268552934], [47.82659065627814, 53.24415132601518], [47.82896745355428, 53.264058763207785], [47.82896745355428, 53.29674372981299], [47.83134425083045, 53.32088611953456], [47.79569229168806, 53.35494625525029], [47.72914196795556, 53.4017345366877], [47.69111321153693, 53.44280908364267], [47.688736414260795, 53.471113241671794], [47.688736414260795, 53.49939853623131], [47.69586680608928, 53.51070737355606], [47.70062040064165, 53.526252098949975], [47.71488118429858, 53.547440261412255]]],
+            [[[48.35423965158571, 54.624010155021], [48.35423965158571, 54.65289635381298], [48.38276121889965, 54.69206623520562], [48.4112827862136, 54.71678564468656], [48.44336954944171, 54.71266678924705], [48.454065137184465, 54.696187182997086], [48.43623915761327, 54.66733175850209], [48.421978373956286, 54.65702127853178], [48.41484798212784, 54.63432901042865], [48.4112827862136, 54.621946069788], [48.38276121889965, 54.61162407272107], [48.35423965158571, 54.624010155021]]],
+            [[[49.388582212882945, 53.56544186354657], [49.360060645569, 53.57955540821719], [49.329162280978885, 53.59507486687517], [49.33629267280736, 53.61199868618614], [49.37907502377829, 53.61763845242989], [49.407596591092236, 53.62045805304135], [49.436118158406146, 53.6091785205424], [49.455132536615444, 53.59648544416233], [49.45988613116775, 53.58378855305856], [49.438494955682316, 53.56544186354657], [49.41235018564458, 53.55979512660715], [49.388582212882945, 53.56544186354657]]]
+        ]
+    }
+}
+]
+}
\ No newline at end of file
diff --git a/tests/data/dataset_with_media/languages.csv b/tests/data/dataset_with_media/languages.csv
new file mode 100644
index 0000000..a4251ae
--- /dev/null
+++ b/tests/data/dataset_with_media/languages.csv
@@ -0,0 +1,3 @@
+ID,Name,Speaker_Area
+1,Erzya,3
+2,Erzya,4
\ No newline at end of file
diff --git a/tests/data/dataset_with_media/media.csv b/tests/data/dataset_with_media/media.csv
index dc061ed..2b0e33c 100644
--- a/tests/data/dataset_with_media/media.csv
+++ b/tests/data/dataset_with_media/media.csv
@@ -1,3 +1,5 @@
 ID,Name,Description,Media_Type,Download_URL
 1,x,y,text/plain,"data:text/plain;base64,SGVsbG8sIFdvcmxkIQ=="
-2,y,x,text/plain;charset=UTF-8,"data:;base64,w6TDtsO8"
\ No newline at end of file
+2,y,x,text/plain;charset=UTF-8,"data:;base64,w6TDtsO8"
+3,z,,application/geo+json,erzya.geojson
+4,z,,application/geo+json,erzya2.geojson
\ No newline at end of file
diff --git a/tests/data/dataset_with_media/metadata.json b/tests/data/dataset_with_media/metadata.json
index 93fdad9..4b67d3a 100644
--- a/tests/data/dataset_with_media/metadata.json
+++ b/tests/data/dataset_with_media/metadata.json
@@ -4,6 +4,35 @@
   "dialect": {"commentPrefix": null},
   "rdf:ID": "dswm",
   "tables": [
+    {
+    "url": "languages.csv",
+    "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#LanguageTable",
+    "tableSchema": {
+        "columns": [
+            {
+                "name": "ID",
+                "required": true,
+                "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+                "datatype": {
+                    "base": "string",
+                    "format": "[a-zA-Z0-9_\\-]+"
+                }
+            },
+            {
+                "name": "Name",
+                "required": false,
+                "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#name",
+                "datatype": "string"
+            },
+            {
+                "name": "Speaker_Area",
+                "required": false,
+                "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#speakerArea",
+                "datatype": "string"
+            }
+        ]
+    }
+},
     {
       "url": "media.csv",
       "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#MediaTable",
diff --git a/tests/data/textcorpus/languages.csv b/tests/data/textcorpus/languages.csv
new file mode 100644
index 0000000..b653048
--- /dev/null
+++ b/tests/data/textcorpus/languages.csv
@@ -0,0 +1,2 @@
+ID,Name,Glottocode
+l1,Tsez,dido1241
\ No newline at end of file
diff --git a/tests/data/textcorpus/lines.csv b/tests/data/textcorpus/lines.csv
new file mode 100644
index 0000000..881a4e2
--- /dev/null
+++ b/tests/data/textcorpus/lines.csv
@@ -0,0 +1,4 @@
+ID,Language_ID,Primary_Text,Analyzed_Word,Gloss,Translated_Text,Meta_Language_ID,Comment,Text_ID,Position,Example_ID,Grammaticality_Judgement
+e1,l1,second line,der	in	halt,i	dont	know,no idea,l2,,1,1 2,,
+e2,l1,first line,der	in	halt,i	dont	know,no idea,l2,,1,1 1,,*
+e2-alt,l1,first line,,,alt,l1,,,,e2,
\ No newline at end of file
diff --git a/tests/data/textcorpus/metadata.json b/tests/data/textcorpus/metadata.json
new file mode 100644
index 0000000..8f87ce3
--- /dev/null
+++ b/tests/data/textcorpus/metadata.json
@@ -0,0 +1,177 @@
+{
+    "@context": [
+        "http://www.w3.org/ns/csvw",
+        {
+            "@language": "en"
+        }
+    ],
+    "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#TextCorpus",
+    "dialect": {
+        "commentPrefix": null
+    },
+    "tables": [
+      {
+        "url": "languages.csv",
+        "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#LanguageTable",
+        "tableSchema": {
+          "columns": [
+            {
+              "name": "ID",
+              "required": true,
+              "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+              "datatype": {
+                "base": "string",
+                "format": "[a-zA-Z0-9_\\-]+"
+              }
+            },
+            {
+              "name": "Name",
+              "required": false,
+              "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#name",
+              "datatype": "string"
+            },
+            {
+              "name": "Glottocode",
+              "required": false,
+              "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#glottocode",
+              "datatype": {
+                "base": "string",
+                "format": "[a-z0-9]{4}[1-9][0-9]{3}"
+              },
+              "valueUrl": "http://glottolog.org/resource/languoid/id/{Glottocode}"
+            }
+          ]
+        }
+      },
+        {
+            "url": "lines.csv",
+            "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#ExampleTable",
+            "tableSchema": {
+                "columns": [
+                    {
+                        "name": "ID",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+                        "datatype": {
+                            "base": "string",
+                            "format": "[a-zA-Z0-9_\\-]+"
+                        }
+                    },
+                  {
+                    "name": "Text_ID",
+                    "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#contributionReference",
+                    "datatype": "string"
+                  },
+                    {
+                        "name": "Language_ID",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#languageReference",
+                        "dc:extent": "singlevalued",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Primary_Text",
+                        "required": true,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#primaryText",
+                        "dc:description": "The example text in the source language.",
+                        "dc:extent": "singlevalued",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Analyzed_Word",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#analyzedWord",
+                        "dc:description": "The sequence of words of the primary text to be aligned with glosses",
+                        "dc:extent": "multivalued",
+                        "datatype": "string",
+                        "separator": "\t"
+                    },
+                    {
+                        "name": "Gloss",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#gloss",
+                        "dc:description": "The sequence of glosses aligned with the words of the primary text",
+                        "dc:extent": "multivalued",
+                        "datatype": "string",
+                        "separator": "\t"
+                    },
+                    {
+                        "name": "Translated_Text",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#translatedText",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "The translation of the example text in a meta language",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "Meta_Language_ID",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#metaLanguageReference",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "References the language of the translated text",
+                        "datatype": "string"
+                    },
+                    {
+                        "name": "LGR_Conformance",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#lgrConformance",
+                        "dc:extent": "singlevalued",
+                        "dc:description": "The level of conformance of the example with the Leipzig Glossing Rules",
+                        "datatype": {
+                            "base": "string",
+                            "format": "WORD_ALIGNED|MORPHEME_ALIGNED"
+                        }
+                    },
+                  {
+                    "name": "Example_ID",
+                    "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#exampleReference",
+                    "dc:extent": "singlevalued",
+                    "datatype": "string"
+                  },
+                  {
+                    "name": "Position",
+                    "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#position",
+                    "separator": " ",
+                    "datatype": "integer"
+                  },
+                  {
+                    "name": "Comment",
+                    "required": false,
+                    "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#comment",
+                    "datatype": "string"
+                  },
+                    {
+                        "name": "Grammaticality_Judgement",
+                        "required": false,
+                        "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#grammaticalityJudgement",
+                        "datatype": "string"
+                    }
+                ]
+            }
+        },
+      {
+        "url": "texts.csv",
+        "dc:conformsTo": "http://cldf.clld.org/v1.0/terms.rdf#ContributionTable",
+        "tableSchema": {
+          "columns": [
+            {
+              "name": "ID",
+              "required": true,
+              "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#id",
+              "datatype": {
+                "base": "string",
+                "format": "[a-zA-Z0-9_\\-]+"
+              }
+            },
+            {
+              "name": "Name",
+              "required": false,
+              "propertyUrl": "http://cldf.clld.org/v1.0/terms.rdf#name",
+              "datatype": "string"
+            }
+          ]
+        }
+      }
+
+    ]
+}
\ No newline at end of file
diff --git a/tests/data/textcorpus/texts.csv b/tests/data/textcorpus/texts.csv
new file mode 100644
index 0000000..6e75585
--- /dev/null
+++ b/tests/data/textcorpus/texts.csv
@@ -0,0 +1,3 @@
+ID,Name
+1,The text
+2,Text without lines
\ No newline at end of file
diff --git a/tests/test_dataset.py b/tests/test_dataset.py
index fe9dee7..086c775 100644
--- a/tests/test_dataset.py
+++ b/tests/test_dataset.py
@@ -10,8 +10,8 @@
 
 from pycldf.terms import term_uri, TERMS
 from pycldf.dataset import (
-    Generic, Wordlist, StructureDataset, Dictionary, ParallelText, Dataset, GitRepository,
-    make_column, get_modules, iter_datasets, SchemaError)
+    Generic, Wordlist, StructureDataset, Dictionary, ParallelText, Dataset, TextCorpus,
+    GitRepository, make_column, get_modules, iter_datasets, SchemaError)
 from pycldf.sources import Sources
 
 
@@ -25,6 +25,11 @@ def ds_wl(tmp_path):
     return Wordlist.in_dir(tmp_path)
 
 
+@pytest.fixture
+def ds_tc(tmp_path):
+    return TextCorpus.in_dir(tmp_path)
+
+
 @pytest.fixture
 def ds_wl_notables(tmp_path):
     return Wordlist.in_dir(str(tmp_path), empty_tables=True)
@@ -94,8 +99,9 @@ def test_provenance(ds, tmp_path):
     assert ds.properties['prov:wasDerivedFrom']['dc:created']
 
 
-def test_primary_table(ds):
+def test_primary_table(ds, ds_tc):
     assert ds.primary_table is None
+    assert ds_tc.primary_table is not None
 
 
 def test_components(ds):
@@ -832,7 +838,7 @@ def test_get_modules():
 
 @pytest.mark.filterwarnings('ignore::UserWarning')
 def test_iter_datasets(data, tmp_path, csvw3, caplog):
-    assert len(list(iter_datasets(data))) == 10 if csvw3 else 11
+    assert len(list(iter_datasets(data))) == 11 if csvw3 else 12
 
     if csvw3:
         assert 'Reading' in caplog.records[0].msg
@@ -938,3 +944,7 @@ def test_Dataset_set_sources(ds):
     src = Sources()
     ds.sources = src
     assert ds.sources is src
+
+
+def test_StructureDataset(structuredataset_with_examples):
+    assert len(structuredataset_with_examples.features) == 2
diff --git a/tests/test_media.py b/tests/test_media.py
index 6cb63ff..257ceaa 100644
--- a/tests/test_media.py
+++ b/tests/test_media.py
@@ -211,3 +211,7 @@ def test_Media_validate(tmp_path):
     ds['MediaTable', 'ID'].valueUrl = ''
     ds.write(MediaTable=[dict(ID='123', Media_Type='text/plain')])
     assert not ds.validate(log=logging.getLogger('test'))
+
+
+def test_Media_validate2(dataset_with_media):
+    assert dataset_with_media.validate()
diff --git a/tests/test_orm.py b/tests/test_orm.py
index ef12879..f5807ef 100644
--- a/tests/test_orm.py
+++ b/tests/test_orm.py
@@ -200,3 +200,34 @@ def test_columnspec(tmp_path):
     v = ds.objects('ValueTable')[0]
     assert v.cldf.value == '1 2 3'
     assert v.typed_value == [1, 2, 3]
+
+
+def test_TextCorpus(textcorpus):
+    assert len(textcorpus.texts) == 2
+
+    e = textcorpus.get_object('ExampleTable', 'e2')
+    assert e.alternative_translations
+
+    text = e.text
+    assert text
+    assert text.sentences[0].id == 'e2'
+
+    assert textcorpus.get_text('2').sentences == []
+
+    assert len(textcorpus.sentences) == 2
+    assert textcorpus.sentences[0].cldf.primaryText == 'first line'
+
+    with pytest.raises(ValueError) as e:
+        textcorpus.validate()
+    assert 'ungrammatical' in str(e)
+
+
+def test_speakerArea(dataset_with_media):
+    lang = dataset_with_media.objects('LanguageTable')[0]
+    sa = lang.speaker_area
+    assert sa.scheme == 'file'
+    assert sa
+    assert sa.mimetype.subtype == 'geo+json'
+    assert 'properties' in lang.speaker_area_as_geojson_feature
+
+    assert dataset_with_media.objects('LanguageTable')[1].speaker_area_as_geojson_feature