If the Firefox user interface (toolbars) is in the wrong language or if you want to change the current language, download Firefox in the language of your choice. *https://www.mozilla.org/en-US/firefox/all/#product-desktop-release The first language setting in Settings is about the language for the user interface. The second language setting in Settings is about the preferred languages for webpages. *Settings -> General -> Language and Appearance -> Language *https://support.mozilla.org/en-US/kb/use-firefox-another-language *https://support.mozilla.org/en-US/kb/choose-display-languages-multilingual-web-pages