If the Firefox user interface (toolbars) is in the wrong language or if you want to change the current language then download Firefox in the language of your choice. You can find the full version of the current Firefox release (87.0) in all languages and all operating systems here: *https://www.mozilla.org/en-US/firefox/all/#product-desktop-release *https://www.mozilla.org/en-US/firefox/87.0/releasenotes/ ---- The setting in Options/Preferences is about the language for the user interface and the preferred language for webpages. *Options/Preferences -> General -> Language and Appearance *https://support.mozilla.org/en-US/kb/use-firefox-another-language *https://support.mozilla.org/en-US/kb/choose-display-languages-multilingual-web-pages