They use Mandarin in there i believe, actually in my opinion when i was watching the show i think it was more used as an umph factor rather then just swearing i can't remember the episode but i know Firefly was being tracked at one point by a guy, and he said "dong ma" was basically means understand, i kind of felt it kind of i don't know how to explain, thats how i feel about it anyways.
I think the alliance is just based on the fact if things are heading the way they are no, not counting anything that may happen in the future the 2 most powerful people in this field would be China and the US, but thats why they call it science fiction.