Doesn't work. I can write any spelling at all on Twitter and it does nothing.

It do nothing. I have installed the English pack and I still only have the Swedish dictionary.

There have been a few instances where certain forms of a word are detected as false positives, but those are low enough to not be inconvenient. (I have only experienced the dictionary part of it - in case there is more to it)

thanks

J'ai vécu en Angleterre (et non au Royaume Uni) j'y ai fait une partie de mes études, mais de grâce ne gâchons pas cete langue.
N'oublions pas que c'est la langue de SHAKESPEARE .

Doesn't work

ok

Not sure who is to blame, but firefox spellchecker is terrible. The suggestions are wide of the mark, and many words on the list are spelt incorrectly themselves. Very odd.