According to the "out of Africa" hypothesis, modern humans evolved in Africa several hundred thousand years ago. Then, from about 50,000 years ago, our ancestors ventured farther afield, ultimately settling worldwide. This is supported by genetic studies, which confirm that the richest genetic diversity is seen amongst African natives, and the least amongst those populations at the tips of the migratory branches early humans followed around the world. But now a scientist at the University of Auckland has added another layer of complexity to the story - the role that human language might have played in the exodus from Africa.
Writing in Science, Quentin Atkinson analysed the number of phonemes - the units of sound that make up words - used in 504 world languages. As a general, rather like genetic diversity, languages spoken by large populations tend to have more phonemes than languages spoken by small or bottle-necked populations. Strikingly, this language phoneme count matches up very closely with the migration pathways predicted by previous genetic and morphological studies.
The African languages are the most richly endowed with phonemes while those languages spoken by peoples at the distant tips of the migratory branches contain the fewest. The implication of this result is that, for the relationship to fit, language must have evolved amongst modern humans whilst they were still in Africa. According to Atkinson "to the extent that language is a marker of cultural identity, our cultural ancestry, like our genetic ancestry, can be traced all the way back to Africa, which I think is quite remarkable." And this acquisition of language is, Atkinson thinks, probably the catalyst that mobilised early man out of Africa. "Humans carried with them in their toolkit from Africa, language, and all the advantages that confers, including coordination and cooperation, giving us a competitive advantage."