diff --git a/README.md b/README.md
index 25a354b..acd5735 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,15 @@ Headers:
 
 Rotating the token in Desktop invalidates the value stored by the extension.
 
+## Language
+
+The popup settings provide a persisted `System / English / Russian` language
+selector. `System` follows the browser UI language: Russian browser locales use
+Russian, and all other locales use English.
+
+The extension and desktop application store their language choices
+independently. Changing one does not change the other.
+
 Payload:
 
 ```json
diff --git a/scripts/build-extension.js b/scripts/build-extension.js
index 69c48cc..a1b8616 100755
--- a/scripts/build-extension.js
+++ b/scripts/build-extension.js
@@ -38,6 +38,13 @@ function copyIcons(destRoot) {
   }
 }
 
+function copyLocalization(destRoot) {
+  copy(path.join(shared, 'i18n.js'), path.join(destRoot, 'i18n.js'));
+  for (const locale of ['en', 'ru']) {
+    copy(path.join(shared, 'locales', `${locale}.json`), path.join(destRoot, 'locales', `${locale}.json`));
+  }
+}
+
 rm(dist);
 
 const chromiumDist = path.join(dist, 'chromium');
@@ -47,18 +54,21 @@ concat([
   path.join(shared, 'protocol.js'),
   path.join(shared, 'api.js'),
   path.join(shared, 'queue.js'),
+  path.join(shared, 'i18n.js'),
   path.join(shared, 'background.js'),
 ], path.join(chromiumDist, 'background.js'));
 copyPopup(chromiumDist);
 copyIcons(chromiumDist);
+copyLocalization(chromiumDist);
 
 const firefoxDist = path.join(dist, 'firefox');
 mkdir(firefoxDist);
 copy(path.join(root, 'firefox', 'manifest.json'), path.join(firefoxDist, 'manifest.json'));
-for (const name of ['protocol.js', 'api.js', 'queue.js', 'background.js']) {
+for (const name of ['protocol.js', 'api.js', 'queue.js', 'i18n.js', 'background.js']) {
   copy(path.join(shared, name), path.join(firefoxDist, name));
 }
 copyPopup(firefoxDist);
 copyIcons(firefoxDist);
+copyLocalization(firefoxDist);
 
 console.log('built dist/chromium and dist/firefox');
diff --git a/scripts/test-background-i18n.js b/scripts/test-background-i18n.js
index e2ea9e5..e37f277 100644
--- a/scripts/test-background-i18n.js
+++ b/scripts/test-background-i18n.js
@@ -34,9 +34,9 @@ const browser = {
     },
   },
   contextMenus: {
-    removeAll(callback) {
+    removeAll() {
       menuTitles = [];
-      if (callback) callback();
+      return Promise.resolve();
     },
     create(item) {
       menuTitles.push(item.title);
diff --git a/scripts/test-i18n.js b/scripts/test-i18n.js
index 6a7ade6..5ddcc47 100644
--- a/scripts/test-i18n.js
+++ b/scripts/test-i18n.js
@@ -33,6 +33,18 @@ assert.strictEqual(tEn('error.value', { error: 'offline' }), 'Error: offline');
 assert.strictEqual(tRu('missing', null, 'Fallback'), 'Fallback');
 assert.strictEqual(tRu('missing.key'), 'missing.key');
 
+const dist = path.join(root, 'dist');
+if (fs.existsSync(dist)) {
+  for (const target of ['chromium', 'firefox']) {
+    for (const relativePath of ['i18n.js', 'locales/en.json', 'locales/ru.json']) {
+      assert.ok(
+        fs.existsSync(path.join(dist, target, relativePath)),
+        `${target} build is missing ${relativePath}`,
+      );
+    }
+  }
+}
+
 i18n.loadCatalogs((locale) => Promise.resolve(locale === 'ru' ? ru : en))
   .then((catalogs) => {
     assert.strictEqual(catalogs.en, en);
diff --git a/shared/background.js b/shared/background.js
index 5e84e99..dfdbf41 100644
--- a/shared/background.js
+++ b/shared/background.js
@@ -139,12 +139,22 @@
       var locale = i18n.resolveLocale(results[0].language, browserLocale());
       var t = i18n.createTranslator(results[1], locale);
       return new Promise(function (resolve) {
-        ext.contextMenus.removeAll(function () {
+        var created = false;
+        function createMenus() {
+          if (created) return;
+          created = true;
           ext.contextMenus.create({ id: 'verstak-capture-page', title: t('context.sendPage', null, 'Send page to Verstak'), contexts: ['page'] });
           ext.contextMenus.create({ id: 'verstak-capture-selection', title: t('context.sendSelection', null, 'Send selection to Verstak'), contexts: ['selection'] });
           ext.contextMenus.create({ id: 'verstak-capture-link', title: t('context.sendLink', null, 'Send link to Verstak'), contexts: ['link'] });
           resolve();
-        });
+        }
+        var removal;
+        try {
+          removal = ext.contextMenus.removeAll(createMenus);
+        } catch (_) {
+          removal = ext.contextMenus.removeAll();
+        }
+        if (removal && typeof removal.then === 'function') removal.then(createMenus, createMenus);
       });
     });
   }