Edit after 2 years of my initial review: still no support for many major languages, after 5 years of development it support only some European languages + Persian (in development). The web is more diverse than that, and Firefox has users all across the globe who use more languages.
For instance Mandarin Chinese is spoken by 1.35 billion, Arabic 710 millions (native+second) and Hindi 610 millions (native+second). Yet these three major languages don't even get any interest from Bergamot team, no promises, nothing at all.
I am sad I'm taking away two stars from my initial review, but I still have hope the situation will change, hopefully in this decade.

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I have been waiting project Bergamot since its first news in 2019, and I am excited that it began to fruit in this extension.
I have just tried it with a few pages, and the translation looks very natural, that's a great success.
However, as many has pointed, the languages supported for the moment are very limited. I hope more languages are going to get supported later.

I am quite satisfied, the translations into my language work 80% so far.
I would definitely appreciate the addition of the option to "Show original", or turn off the translation and display the page in the original language again.

COME ON!
Hope to support Chinese!

Great add-on to run totally offline. But how can you use a Japanese character in logo without supporting Japanese. And as a east Asian user here, a CJK common character instead of a Japanese character would be better. Google uses 文.

Doesn't work at Firefox Nightly - "fxtranslation-notification". Works with Developer Edition. Please fix.

Parabéns por terem lançado esta extensão, agora sim vão ajudar muitos usuários na hora de traduzir inúmeras páginas da web.
Acrescentem também o Português Brasileiro à lista de opções de idiomas para traduzir páginas na futura versão que irá ser lançada.

Atualização do comentário 07-01-2023
Mas o idioma português que existe na extensão é o de Portugal ou do Brasil? Utilizo no Firefox Beta para Android e funciona até bem para traduzir as palavras, só precisa melhorar o enquadramento da janela que está desproporcional e tradução de páginas não está disponível, mas acredito que falta pouco para ficar 100% no FF de Android.

I just want to disable suggestions as there are too many false positives

NO Chinese language and not translation when select words keep up

(note based on v1.1.4)
The first translation in a language is a bit long due to the download of the model, that would be great to speed-up this process.
Also waiting for the ability to translate a text selection.

That's not too much language which I can choose :(

It only allows translations in one direction that is to english and i can't translate from english to spanish that's i need.
Might be it's not working

i wish this add-on will support more language than this and have button translate like simple translate add-on

In der Praxis erscheint am oberen Bildschirmrand lediglich eine Fehlerleiste "fxtranslation-notification". Schade, die Idee ist eigentlich gut, aber das Add-on sollte vor Release getestet werden.

Please add support to android

Disappointed. What bar is this that opens in all the pages? Do it subtly. By right mouse click.