I can't speak languages too well, but I can pretty much read/write any language that's not glyph-related with just a couple hours of work. Its just like breaking code except much much easier because once you know one family of languages, the rest are very similiar in grammar with only the odd few exceptions. Even vocabulary is similiar.
Anyway, I only speak about 4 with varying fluency - I'm trying to learn Swedish right now but have a lack of time to devote to it properly. I can however sing in many different languages - I just can't speak it.