If you have the Firefox user interface (menu bar) in the wrong language or want to change the current language then you can get the language of your choice here: http://www.mozilla.com/firefox/all.html Uninstall the current Firefox version, but make sure that you do not remove your personal data. Install the new Firefox version of the wanted language. See also http://kb.mozillazine.org/Profile_backup and [[Backing up your information]] .......... You may need to (re)set the pref "general.useragent.locale" to the preferred language (e.g. "en-US" or "en-GB") on the about:config page. You can open the '''about:config''' page via the location bar, like you open a web site. Use the ''Filter'' bar at the top of that page to quickly locate the pref.