SAN DIEGO--A genetic study of several hundred people in Africa has revealed that the first human language may have resembled today's African "click" languages, geneticists argue. The proposal is controversial, however.
Found only in Africa, click languages rely on distinctive clicking sounds made by the tongue to form words. Peoples across Africa use click languages, including the Hadza tribe of Tanzania, in eastern Africa, and the San (Bushmen) groups of Botswana and Namibia, in southern Africa.
To determine whether click languages emerged from a common tongue, anthropological geneticists Alec Knight and Joanna Mountain and their colleagues at Stanford University analyzed cells from cheek swabs of several African populations for genetic markers on the Y chromosome, which fathers pass on to sons. The more related click speakers are, Knight reasoned, the more likely it is that click languages arose relatively recently. If click speakers are genetically diverse, that could imply that other speakers lost their clicks after the click speakers diverged into separate populations.
The researchers examined a nucleotide change on the Y chromosome. About half the Hadzabe (plural of Hadza), a third of the San, and a third of non-click speakers in central Africa share the variant, which is not found elsewhere. Limiting their study to just these individuals, the team then looked at another Y chromosome marker. Changes there revealed that the Hadzabe and the San "are as [genetically] distant from one another as two populations could be," Knight reported on 14 October at the annual meeting of the American Society for Human Genetics. Both the San and the Hadzabe appear more similar to the non-click speaking groups than to one another. The researchers dispute the going theory that the San and Hadzabe languages arose independently; the dialects, Mountain says, are too complex for that.
But not everyone buys the anthropologists' claim. "Linguistically, we don't think they're one group, [and] we don't believe they have a common ancestor," says linguist Bonny Sands of Northern Arizona University in Flagstaff.