The Signs in the Silence - S6-E21
Stupidity: Bones realises she could pull a wisdom tooth from Amy in order to identify where she grew up and find her birth parents. Which works, but at no point do they consider simply going through missing person records with the relevant info. They know how old she is, they know roughly when she disappeared, not like there are hundreds of 3 year olds going missing every year, especially not with Waardenburg syndrome. By that age her deafness would have been apparent, which would narrow the pool hugely.
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.