Some web browsers (like Chrome and Edge) can translate web pages, but the feature always requires external services like Google Translate or Bing Translate. Now Firefox can translate pages on your computer without telling Google, Microsoft, or any other translation company what you're looking at.
Mozilla has been working with the University of Edinburgh, Charles University, University of Sheffield, and University of Tartu for a few years on Project Bergamot, which aims to build a text translation engine that runs entirely on someone's computer. That way, no data is ever sent to cloud services, ensuring completely private translation.
Mozilla has now released an extension for Firefox, called Firefox Translations, with the technology developed through Project Bergamot. It looks more or less like the translation features in Chrome or Edge, with a bar appearing at the top of the page if a different language is detected. However, there are far fewer supported languages than Google Translate: English, Spanish, Estonian, German, Czech, Bulgarian, Norwegian Bokmål, Portuguese, and Italian. Also, some translations are one-way only --- for example, it can convert Norwegian to English, but not the other way around.
Even though there aren't many supported languages, and the technology has a long way to go before it can stand toe-to-toe with Google Translate (which itself is not perfect), it's still an impressive achievement. Mozilla said in a blog post, "Our solution to that was to develop a high-level API around the machine translation engine, port it to WebAssembly, and optimize the operations for matrix multiplication to run efficiently on CPUs. That enabled us to not only develop the translations add-on but also allowed every web page to integrate local machine translation, like in this website, which lets the user perform free-form translations without using the cloud."
Mozilla didn't mention when, or if, the feature would be integrated into the Firefox browser instead of requiring an extra extension. Still, you can give it a try by downloading the extension from the Firefox Add-ons repository.
Source: Mozilla Blog