diff --git a/_locales/en/messages.json b/_locales/en/messages.json
index 133f942..26aa76b 100644
--- a/_locales/en/messages.json
+++ b/_locales/en/messages.json
@@ -1,4 +1,13 @@
 {
+    "menus_open-in-private-tab": {
+        "message": "Open in Private Tab"
+    },
+    "menus_open-link-in-private-tab": {
+        "message": "Open Link in Private Tab"
+    },
+    "menus_close-all-private-tabs": {
+        "message": "Close all private tabs"
+    },
     "alerts_unable_container_title": {
         "message": "browser.contextualIdentities not available - Private Tabs"
     },
diff --git a/_locales/ja/messages.json b/_locales/ja/messages.json
index 292cd40..2da59d0 100644
--- a/_locales/ja/messages.json
+++ b/_locales/ja/messages.json
@@ -1,4 +1,13 @@
 {
+    "menus_open-in-private-tab": {
+        "message": "プライベートタブで開く"
+    },
+    "menus_open-link-in-private-tab": {
+        "message": "リンクを新しいプライベートタブで開く"
+    },
+    "menus_close-all-private-tabs": {
+        "message": "すべてのプライベートタブを閉じる"
+    },
     "alerts_unable_container_title": {
         "message": "browser.contextualIdentities が利用できません - Private Tabs"
     },
diff --git a/background.js b/background.js
index 07630fc..1a0f0d5 100644
--- a/background.js
+++ b/background.js
@@ -91,17 +91,17 @@ async function deleteHistory(details) {
 
     browser.menus.create({
         id: "open-in-private-tab",
-        title: "Open in Private Tab",
+        title: browser.i18n.getMessage("menus_open-in-private-tab"),
         contexts: ["tab"]
     });
     browser.menus.create({
         id: "open-link-in-private-tab",
-        title: "Open Link in Private Tab",
+        title: browser.i18n.getMessage("menus_open-link-in-private-tab"),
         contexts: ["link"]
     });
     browser.menus.create({
         id: "close-all-private-tabs",
-        title: "Close all private tabs",
+        title: browser.i18n.getMessage("menus_close-all-private-tabs"),
         contexts: ["browser_action"]
     });
     browser.menus.onClicked.addListener(async (e) => {