Subject: The Voice

Recently, something interesting happened. I had been communicating, via 
telephone, with a business associate. We had extensive conversations. When we 
met, he was surprised because he did not know I was black. I have friends who 
say they are not surprised an individual would be unable to detemine my ethnic 
background from a phone conversation;I don't "sound" black. 

What makes white people "sound white" and black people "sound black"? I am not 
refering to grammer or the use of cultural dialects. It seems that regardless of 
region of the US or nationality there is something about a person's voice that 
signals there ethnic background.

Any explanation or a resource would be helpful. Also, is there a good book which 
explains the development of accents and dialects within the English language.

Re: The Voice