https://addons.mozilla.org/en-US/firefox/addon/linguist-translator/ https://addons.mozilla.org/en-US/firefox/addon/linguist-tran... Includes offline translatio

https://addons.mozilla.org/en-US/firefox/addon/linguist-translator/ https://addons.mozilla.org/en-US/firefox/addon/linguist-tran... Includes offline translation. I very rarely need this, so I can’t speak about the quality, though.