Reading through the thread about nations surviving into the 24th century got me wondering about languages. Of course the shows make almost constant use of universal translators to avoid having to explain this sort of thing, but we know there must be quite a few languages across the Federation.
So I'm wondering: how much do the characters on the show actually really understand each other?
Did Spock learn English because of his mother? Do Odo and Kira really spend all their time speaking Bajoran? Does Picard actually speak French all the time? Have any earth languages other than english actually survived?
Do the Betazoids and the Risians even have their own language?
If you disabled every universal translator, would a Federation starship be rendered almost completely unable to function, or is English just the standard language of the organization, with extensive english lessons at the academy?
And what about the Federation Council? In STIV, the clearly non-human Federation President seems to speak entirely in English. Is that translation or do the other member states really not care that even the council itself is entirely earth-centric?