If you need translations in your browser, you can use several addons from https://addons.mozilla.org If you are interested in a "native" in-browser feature, consider voting for and following this thread at Mozilla Connect: https://connect.mozilla.org/t5/ideas/get-built-in-translation-feature/idi-p/5347 By the way Firefox Translations is already in the works, but we don't know when will it be released and which languages will it support.