Maybe I'm asking for trouble by bringing this up on 4chan, but I'm really interested in this, actually. Why do different races have different voices? Not dialects, not language, but sounds of their voices all together? For instance, you can record a black man, a white man, an Asian man, and a Latino man (or women) with virtually no accent, have them speak the same line, and you'd be able to comfortably identify which race each belongs to. I'm not exactly sure why. Race seems to demarcated by a mix of physiological and social boundaries but it's hard to tell.

Anyone know anything on, say, the physiology of race and voice? Again, I'm really not trying to make a bait thread or whatever, so no racism, please :3
(maybe that's wishful thinking on 4chan, but whatever)