I will only point out two caveats: - We cannot assume that click
speakers of the African Southwest are necessarily indigenous to
that region, and - It is possible that, the greater phonemic
diversity is due to ancient admixture between quite divergent
peoples who possessed two different types of phonemic
inventories, while most Africans inherited only the phonemic
inventory of one of these peoples, which then decayed as per the
author's theory away from Africa. Science 15 April 2011: Vol.
332 no. 6027 pp. 346-349 Phonemic Diversity Supports a Serial
Founder Effect Model of Language Expansion from Africa Quentin
D. Atkinson Human genetic and phenotypic diversity declines with
distance from Africa, as predicted by a serial founder effect in
which successive population bottlenecks during range expansion
progressively reduce diversity, underpinning support for an
African origin of modern humans. Recent work suggests that a
similar founder effect may operate on human culture and
language. Here I show that the numb