This is a fighting game with blood, pain and death.
But you're worried about bad language?
Fake blood, fake pain, fake death, real language, real insults. I think that should make it clear.
Go look at Runescape, hoards of 10/12y olds that are enormously inventive at circumventing the censor (and that censor is pretty big).
The American thing was pointed at:(example) Biggest porn industry on the planet, but a tit on tv is a HUGE scandal.
(You kill humans, you like it when you slash/shoot someone to death, you gain respect and money by doing it but you're scandalized by someone that uses a curse?)
PIE, Isn't that just spamming? (when one does such a thing, it doesn't really matter if he says DAMN or PIE, it's just annoying)
Always calling somebody a fag/mofo/.... when you get killed should be treated as griefing while the usual 'goddamned, you fucking dodged my damn headbites like hell!' is fairly regular and non-disturbing imho.
Maybe it's just me but i grew up and learned a lot of curse-words through internet communities where they're used fairly much in a good way, a friendly way (or at least a non-insulting way)
Learning when and with whom to use curse-words(good/bad way doesn't matter) is a lot better then to put up a huge censor which will get circumvented anyways...