Map showing origin and spread of language from southern Africa. Graphic from the journal Science and the New York Times.(View Larger)
Quentin D. Atkinson of the University of Auckland, New Zealand published "Phonemic Diversity Supports a Serial Founder Effect Model of Language Expansion from Africa," Science 15 April 2011: Vol. 332 no. 6027 pp. 346-349 DOI: 10.1126/science.1199295.
"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 number of phonemes used in a global sample of 504 languages is also clinal and fits a serial founder–effect model of expansion from an inferred origin in Africa. This result, which is not explained by more recent demographic history, local language diversity, or statistical non-independence within language families, points to parallel mechanisms shaping genetic and linguistic diversity and supports an African origin of modern human languages" (Abstract)
"The detection of such an ancient signal in language is surprising. Because words change so rapidly, many linguists think that languages cannot be traced very far back in time. The oldest language tree so far reconstructed, that of the Indo-European family, which includes English, goes back 9,000 years at most.
"Quentin D. Atkinson, a biologist at the University of Auckland in New Zealand, has shattered this time barrier, if his claim is correct, by looking not at words but at phonemes — the consonants, vowels and tones that are the simplest elements of language. He has found a simple but striking pattern in some 500 languages spoken throughout the world: a language area uses fewer phonemes the farther that early humans had to travel from Africa to reach it.
"Some of the click-using languages of Africa have more than 100 phonemes, whereas Hawaiian, toward the far end of the human migration route out of Africa, has only 13. English has 45 phonemes" (http://www.nytimes.com/2011/04/15/science/15language.html?hp, accessed 04-15-2011).