Be careful with old versions!
These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.
For LocalLingvo mode: now can translate from russian.
And can open translated word in a new tab!
Supported English, German, Franch, Italian, Spain to Russian and vice versa.
Lingvo.ru or Lingvo.Yandex.ru
You need only install extension, restart FireFox and use... - select some word on page, right mose button click on selection and click "Translate with Lingvo" - thats all.