Given that the US has subcultures from all over the world, I wouldn't be at all surprised to find any given language spoken in Liberty, realistically speaking.
That said, Freelancer is based on very strict astrographical divisions between stereotypical ethnic and cultural groups, so I also wouldn't be surprised if the answer was no.
Of course, if you wanted to roleplay that there was some descendants of French Canadians living together someplace, I don't think that would be terribly unreasonable, especially since there would have been no French-speaking house for them to immigrate to (the way other subcultures could have).
However, it also might be worth considering that such a group could be suffering from prejudice and that sort of thing in light of Gallia's aggressiveness, and there may be some pressure for them to move.
