Player Under Pressure - S3-E11
Trivia: This episode's airing was postponed for almost a year following the Virginia Tech massacre. Coincidentally, a similar event happened to David Boreanaz almost exactly eight years earlier when the "Buffy the Vampire Slayer" episode "Earshot" was postponed following the Columbine school massacre.
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.