Other mistake: At the start, when Hodgins gives his findings at the scene a fly can be seen crawling over the camera lens. (00:02:00)
Other mistake: Bones produces a gun and states that she got it herself. However it is explained in earlier episodes she is not legally allowed a weapon due to being arrested for shooting a suspect.
Answer: Since the palatine bone is a bone that helps form the mouth it has a lot to do with speaking. The shape of it differs a lot depending on your ethnic background. I would guess that they, in the show, meant that the person's bone tells that they were Japanese and that it was "made for the purpose of speaking Japanese." That's what I'd assume anyway. I've studied molecular biology though, so I'm not an expert on bones.