69
Linguist, an ultimate translation browser extension
(vitonsky.net)
All about open source! Feel free to ask questions, and share news, and interesting stuff!
Community icon from opensource.org, but we are not affiliated with them.
... If all you need is western European languages translation. If you need to translate any African or Asian language, you are SOL.
If you need languages other than "western European languages", you're SOL with this offline translator; whether you use it within Firefox or the extension.