Firefox problem with languages

['Forum Post]

I have a similar problem (maybe identical), i use firefox in swedish,
but some extensions like "tab mix plus", "gmail notifier" and some
others is all in spanish (i think), guessing there have been a problem
with SE vs ES. 

I tried the above suggestion, but it only worked for a short while (and
then in english), after the nex restar of firefox it all was in spanish
again.



Does anyone have a fix for this?


-- 
jonasmattsson