The Independent

London

Scientists have found that echoes of the earliest language spoken by ancient humans tens of thousands of years ago have been preserved in the distinctive clicking sounds still spoken by some African tribes.

The clicks made by the San people of southern Africa and the Hadzabe of East Africa are the linguistic equivalent of living fossils preserved from a much older and primitive tongue, probably spoken by most of the humans who lived more than 40,000 years ago.

A study by geneticists and linguists has found that people, who use click sounds today have almost certainly inherited them from a common ancestor who spoke one of the earliest

proto-languages.

The investigation by a team led by Joanna Mountain and Alec Knight of Stanford University in California centred on the genetic relationship between the Hadzabe of north-central Tanzania and the Ju’hoansi San who live on the Nambia-Botswana border.

Although separated by thousands of miles, both groups use the same sort of click sounds and accompanying consonants to communicate; yet their DNA shows that they are unrelated and must have been geographically separated for at least 40,000 years.

More than 30 languages in southern Africa are characterised by a repertoire of click consonants and a few are also known in East Africa. For decades, linguists have assumed that the click languages are all related and must have derived from a common source relatively recently.

The most obvious explanation is that the clicks have been invented independently in the two isolated regions. But Dr Knight and Professor Mountain discount this because a common origin is the most likely explanation for the similarity of the clicks and the way they are used in the languages of East and southern Africa.

“The hypothesis of independent invention, as it applies to the languages of the Hadzabe and San, lacks linguistic support,” the scientists say. Another suggestion is that one group has “borrowed” click speaking from another but this would have brought the two people in close contact over a long period of time and should have resulted in some interbreeding that would be seen in their DNA.

Another reason, but unlikely, is that click speaking is difficult to learn for adults because of the tongue distortions it requires. Borrowing the full repertoire of clicks would be almost impossible for non-native speakers, the scientists say.

A third possibility is that the genetic evidence might be tainted in some way by interbreeding with neighbouring tribes to produce an effect known as “gene flow” with non-click speakers. Tests on neighbouring tribes show that this is unlikely.

“The remaining explanation involves independent retention of clicks, possibly for tens of thousands of years, in separate populations leading to the present-day San and Hadzabe,” the scientists say. “The deep genetic divergence between the click-speaking groups is consistent with the hypothesis that clicks are an ancient element of human language. If, in fact, San-Hadzabe separation dates back to a time prior to out-of-Africa expansions of modern humans, clicks may be more than 40,000 years old.

One probable scenario is that click speaking came about because it helped people to communicate while hunting — animals are known to be scared by human language but take little notice of click speaking.

Because of this advantage it quickly spread as anatomically modern humans migrated out of their East African cradle around the Great Rift Valley into southern Africa. But many of these small, regional populations could easily have lost their click vocabulary in different hunting environments.