From San Diego, at a meeting of the American Society of Human Genetics
Some tribes in Africa speak to each other with a vocabulary that includes sharp clicking sounds. Genetic comparison of two such tribes suggests that the unusual click languages, known as Khoisan languages, could resemble the ancestral tongue of all humankind.
For more than a century, linguists have debated the origins of these click languages, notes Alec Knight of Stanford University. These tongues are most prevalent in southwestern Africa where many tribes, including the San and !Kung tribes (the ! represents a click sound), speak them. The Hadzabe people and several other tribes in the East African country of Tanzania also talk with clicks. The geographic diversity of Khoisan tongues, Africa's apparent role as the birthplace of humanity, and other clues have led some scientists to propose that all living humans descended from speakers of a click language.