I don't think so. Just because the elves and humans know the tongue of spirits as "Sylvan" doesn't mean it's not the same tongue that psuedo-asians know as "spirit tongue." It's just two cultures looking at the same sort of creatures from different angles.
Would it disturb you to know that the "formians" referred to by the psuedo-celtic culture in my game world are really Oni? Both are sort of mishapen supernatural giants, so it made sense to me, and fit the campaign circumstances.
No, that wouldn't disturb me too much -- there's a lot of ways to explain it that make lots of sense. There's an inherent danger in mixing genres like that though that you'll really pull your characters out of the game and the campaign can lose credibility if not handled correctly.