--- a/toolkit/content/widgets/videocontrols.js
+++ b/toolkit/content/widgets/videocontrols.js
@@ -2769,32 +2769,38 @@ this.VideoControlsImplWidget = class {
             <div id="textTrackListContainer" class="textTrackListContainer" hidden="true">
               <div id="textTrackList" class="textTrackList" offlabel="&closedCaption.off;"></div>
             </div>
           </div>
         </div>
       </div>`,
       "application/xml"
     );
+    this.l10n = new this.window.DOMLocalization([
+      "toolkit/global/videocontrols.ftl",
+    ]);
+    this.l10n.connectRoot(this.shadowRoot);
     this.shadowRoot.importNodeAndAppendChildAt(
       this.shadowRoot,
       parserDoc.documentElement,
       true
     );
   }
 
   elementStateMatches(element) {
     let elementInPiP = VideoControlsWidget.isPictureInPictureVideo(element);
     return this.isShowingPictureInPictureMessage == elementInPiP;
   }
 
   destructor() {
     this.Utils.terminate();
     this.TouchUtils.terminate();
     this.Utils.updateOrientationState(false);
+    this.l10n.disconnectRoot(this.shadowRoot);
+    this.l10n = null;
   }
 
   onPrefChange(prefName, prefValue) {
     this.prefs[prefName] = prefValue;
     this.Utils.updatePictureInPictureToggleDisplay();
   }
 
   _setupEventListeners() {

new file mode 100644
--- /dev/null
+++ b/toolkit/locales/en-US/toolkit/global/videocontrols.ftl
@@ -0,0 +1,3 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.