Mozilla 推出了「Firefox Translations」這個 Firefox 上的套件。
主打的就是 offline 這件事情，保有隱私性：
Firefox Translations provides automated translation of web content. Unlike cloud-based alternatives, translation is done locally, on the client-side, so that the text being translated does not leave your machine.
從 Hacker News 上的討論「Firefox Translations: Translate websites in your browser without using the cloud (addons.mozilla.org)」可以看到有些人有提到效果，雖然沒有像雲端服務的準確，但算是可用：
I've just installed it, and I'm impressed so far. I've only run it against some sample German Wikipedia articles (https://de.wikipedia.org/wiki/Clan_of_Xymox), but it produces surprisingly readable text. I also particularly like the "highlight potential errors" option to flag stuff that even the translation service thinks might be a bit off.
It's not nearly as speedy as Google Translate, but I'll take that happily if it means keeping it local.
從頁面上列出的支援語言可以看出還是以歐美用到的語系為主，然後下方也有說明這個專案是包括其他計畫的贊助累積出來的：
Firefox Translations was developed with The Bergamot Project Consortium, coordinated by the University of Edinburgh with partners Charles University in Prague, the University of Sheffield, University of Tartu, and Mozilla. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 825303.
不過比較好奇的是在頁面上有提到 CPU 需要 SSE4.1 能力... 這樣就有兩個問題了，第一個是 browser extension 可以直接跑 SSE4.1 指令集？另外一個疑問就是，Apple 的 ARM 架構就無法支援嗎 (應該也有類似的加速指令集)，現在是 x86 限定？
A CPU that supports SSE4.1 extensions is required for this addon to function properly. If it doesn't, an error will be displayed when the translation is being started.
就算現在限制很多，看起來還是個很有前途的計畫，也許有機會移植到其他瀏覽器上？