Where did humanity utter its first words? A new linguistic analysis attempts to rewrite the story of Babel by borrowing from the methods of genetic analysis – and finds that modern language originated in sub-Saharan Africa and spread across the world with migrating human populations.
Quentin Atkinson of the University of Auckland in New Zealand designed a computer program to analyse the diversity of 504 languages. Specifically, the program focused on phonemes – the sounds that make up words, like “c”, “a”, and “tch” in the word “catch”.
Earlier research has shown that the more people speak a language, the higher its phonemic diversity. Large populations tend to draw on a more varied jumble of consonants, vowels and tones than smaller .
Africa turned out to have the greatest phonemic diversity – it is the only place in the world where languages incorporate clicks of the tongue into their vocabularies, for instance – while South America and Oceania have the smallest. Remarkably, this echoes genetic analyses showing that African populations have higher genetic diversity than European, Asian and American populations.
This is generally attributed to the “serial founder” effect: it’s thought that humans first lived in a large and genetically diverse population in Africa, from which smaller groups broke off and migrated to what is now Europe. Because each break-off group carried only a subset of the genetic diversity of its parent group, this migration was, in effect, written in the migrants’ genes.
Atkinson argues that the process was mirrored in languages: as smaller populations broke off and spread across the world, human language lost some of its phonemic diversity, and sounds that humans first spoke in the African Babel were left behind.
To test this, Atkinson compared the phoneme content of languages around the world and used this analysis to determine the most likely origin of all language. He found that sub-Saharan Africa was a far better fit for the origin of modern language than any other location.
“One of the big questions is whether there was a single origin of language”, or if it emerged in parallel in different locations, says Atkinson. “This suggests there was one major origin in Africa.”
“It’s a compelling idea,” says Sohini Ramachandran of Brown University in Providence, Rhode Island, who studies population genetics and human evolution. “Language is such an adaptive thing that it makes sense to have a single origin before the diaspora out of Africa. It’s also a nice confirmation of what we have seen in earlier genetic studies. The processes that shaped genetic variation of humans may also have shaped cultural traits.”
The findings are likely to create something of a stir among linguists, who have typically been reluctant to draw conclusions about how languages were evolving at the dawn of humanity. “Most linguists do not think it’s possible to trace linguistic history past 10,000 years,” says Merritt Ruhlen of Stanford University, California. “There is a lot of anger and tension surrounding that kind of analysis.”
“The study deals with something that happened maybe 50,000 to 100,000 years ago, which is not even close to the time span that most linguists are comfortable with,” agrees his colleague Brenna Henn, who nonetheless agrees with its conclusions. “Most linguists say you can’t possibly provide evidence of how languages were related to each other that long ago.”
Journal reference: Science, DOI: 10.1126/science.1199295