--- a/browser/base/content/tabbrowser.js
+++ b/browser/base/content/tabbrowser.js
@@ -5491,21 +5491,21 @@ var TabContextMenu = {
       toggleMute.accessKey = gNavigatorBundle.getString("muteTab.accesskey");
     }
 
     // Adjust the state of the toggle mute menu item for multi-selected tabs.
     if (this.contextTab.hasAttribute("activemedia-blocked")) {
       toggleMultiSelectMute.label = gNavigatorBundle.getString("playTabs.label");
       toggleMultiSelectMute.accessKey = gNavigatorBundle.getString("playTabs.accesskey");
     } else if (this.contextTab.hasAttribute("muted")) {
-      toggleMultiSelectMute.label = gNavigatorBundle.getString("unmuteSelectedTabs.label");
-      toggleMultiSelectMute.accessKey = gNavigatorBundle.getString("unmuteSelectedTabs.accesskey");
+      toggleMultiSelectMute.label = gNavigatorBundle.getString("unmuteSelectedTabs2.label");
+      toggleMultiSelectMute.accessKey = gNavigatorBundle.getString("unmuteSelectedTabs2.accesskey");
     } else {
-      toggleMultiSelectMute.label = gNavigatorBundle.getString("muteSelectedTabs.label");
-      toggleMultiSelectMute.accessKey = gNavigatorBundle.getString("muteSelectedTabs.accesskey");
+      toggleMultiSelectMute.label = gNavigatorBundle.getString("muteSelectedTabs2.label");
+      toggleMultiSelectMute.accessKey = gNavigatorBundle.getString("muteSelectedTabs2.accesskey");
     }
 
     this.contextTab.toggleMuteMenuItem = toggleMute;
     this.contextTab.toggleMultiSelectMuteMenuItem = toggleMultiSelectMute;
     this._updateToggleMuteMenuItems(this.contextTab);
 
     let selectAllTabs = document.getElementById("context_selectAllTabs");
     selectAllTabs.disabled = gBrowser.allTabsSelected();

--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -849,20 +849,24 @@ userContextOpenLink.label = Open Link in
 
 muteTab.label = Mute Tab
 muteTab.accesskey = M
 unmuteTab.label = Unmute Tab
 unmuteTab.accesskey = m
 playTab.label = Play Tab
 playTab.accesskey = l
 
-muteSelectedTabs.label = Mute Tabs
-muteSelectedTabs.accesskey = u
-unmuteSelectedTabs.label = Unmute Tabs
-unmuteSelectedTabs.accesskey = b
+muteSelectedTabs2.label = Mute Tabs
+# LOCALIZATION NOTE (muteSelectedTabs2.accesskey): The accesskey should
+# match the accesskey for muteTab.accesskey
+muteSelectedTabs2.accesskey = M
+unmuteSelectedTabs2.label = Unmute Tabs
+# LOCALIZATION NOTE (unmuteSelectedTabs2.accesskey): The accesskey should
+# match the accesskey for unmuteTab.accesskey
+unmuteSelectedTabs2.accesskey = m
 playTabs.label = Play Tabs
 playTabs.accesskey = y
 
 # LOCALIZATION NOTE (sendTabsToDevice.label):
 # Semi-colon list of plural forms.
 # See: https://developer.mozilla.org/en/docs/Localization_and_Plurals
 # #1 is the number of tabs sent to the device.
 sendTabsToDevice.label = Send Tab to Device;Send #1 Tabs to Device