"The different kinds of sounds used in different languages" are ALMOST CERTAINLY NOT the "result of small anatomical differences in larynx, tongue, teeth, etc. among ethnic groups"
The evidence can be found in the language acquisition of internationally adopted children. Children with normal physiology adopted before age 2 learn the phonology and phonetics of their new language without any accent or other impediment. See "Speech and Language 'Mythbusters' for Internationally Adopted Children" by Sharon Glennen.
(
http://www.asha.org/Publications/leader ... 81216a.htm)
In particular, see Myth 3, "The child's first language will affect aspect of learning the new adopted language"
Refutation:
"Studies of internationally adopted children under age 2 have found that the first language has no inhibitory or facilitory effect on learning a new language or its phonology."
Or consider the following from Encyclopedia Britannica
http://global.britannica.com/EBchecked/ ... cquisition
"In regard to the production of speech sounds, all humans are physiologically alike. It has been shown repeatedly that children learn the language of those who bring them up from infancy. In most cases these are the biological parents, especially the mother, but one’s first language is acquired from environment and learning, not from physiological inheritance. Adopted infants, whatever their physical characteristics and whatever the language of their actual parents, acquire the language of the adoptive parents.
"Different shapes of lips, throat, and other parts of the vocal tract have an effect on voice quality; this is part of the individuality of each person’s voice referred to above. Physiological differences, including size of throat and larynx, both overall and in relation to the rest of the vocal tract, are largely responsible for the different pitch ranges characteristic of men’s, women’s, and children’s speech. These differences do not affect one’s ability or aptitude to speak any particular language"