The Fair Folk is English of course, it takes some understanding and insight and a hell of a lot of creativity. As it goes even far more beyond the basis of basic role-playing and makes it more chaotic. In other words, it rewards those who has the biggest imagination. ^.^
Now, I have seen a game that would make anyone's head explode. I'd have to find it, it's on the RPG forums somewhere, but it's so damn confusing and detailed, it looks like someone was trying to rewrite the Theory of Relativity in Latin with no understanding of either language, then run it through a Japanese lab technician's hands, then written backwards.
If you understand what I just said, it's complicated like that, times a hundred.