It's good but starting language download is a bit clunky. Couple that with Firefox's terrible design of non-pinnable extension popups, it's hard to use. That's not the extension's fault, that's on Firefox itself.

LATIN, please! Should be easiest of all languages... and never needs updating, except for general accuracy improvements. Then ELIZABETHAN ("Early Modern") ENGLISH, because a ton of that is in the public domain.

Works great so far.
It can optionally "Translate this tab automatically as you browse".
I also like that it is created "By Firefox" :)

i really like your browser, but because there is no russian, i sometimes use chrome. Please add it faster