It’s the result of the E.U.-funded Project Bergamot, which saw Mozilla collaborating with several universities on a set of machine learning tools that would make offline translation possible.

This is important not because many people need to translate in their browsers while offline - like a screen door for a submarine, it’s not really a use case that makes sense - but because the goal is to reduce end reliance on cloud providers with ulterior motives for a task that no longer requires their resources. It will need to download some resources the first time it translates a language, and presumably it may download improved models if needed, but the actual translation work is done by your computer, not in a data center a couple hundred miles away. The translation tool, called Firefox Translations, can be added to your browser here. It’s a huge step forward for a popular service tied strongly to giants like Google and Microsoft.

Mozilla has added an official translation tool to Firefox that doesn’t rely on cloud processing to do its work, instead performing the machine learning–based process right on your own computer.

How to get firefox to translate a page