The Bones on a Blue Line - S5-E15
Other mistake: In the subway tunnel Daisey is surprised to see a white cane and comes to the conclusion the victim was blind, However, in the scene before this, it was established on the forensics platform that the victim was blind due to a surgical implant. (00:12:00)
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.