The Mozilla family applications have a localization system, which allows the use of localized extensions.

Extensions can be localized into as many languages as wanted. If one extension is not available in your language, you can translate it easily.

If you want to translate one of my extensions, please register at BabelZilla. BabelZilla is a team of international translators for Mozilla extensions.

Many extension developers have submitted their extensions, and registered users can translate them using a very simple translation tool: "Web Translation System" (WTS).