The Verdict in the Story - S3-E13
Revealing mistake: At the end where Brennan is waiting outside the courthouse, you can see Booth's (David's) arm. You can see it just to the left of the large column on the right side of the screen. It is there before he leaves the courtroom, and before he walks up. He is supposed to be walking to her from the courtroom, but the actor is instead waiting behind the pillar for his cue.
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.