Psychologists from The University of Auckland have just published two major studies on the diversity of the world’s languages in the journals Science and Nature.

The first study, published in Scienceby Dr Quentin Atkinson, provides strong evidence for Africa as the birthplace of human language.

An analysis of languages from around the world suggests that, like our genes, human speech originated — just once — in sub-Saharan Africa. Atkinson studied the phonemes, or the perceptually distinct units of sound that differentiate words, used in 504 human languages today and found that the number of phonemes is highest in Africa and decreases with increasing distance from Africa.

The fewest phonemes are found in South America and on tropical islands in the Pacific Ocean. This pattern fits a “serial founder effect” model in which small populations on the edge of an expansion progressively lose diversity. Dr Atkinson notes that this pattern of phoneme usage around the world mirrors the pattern of human genetic diversity, which also declined as humans expanded their range from Africa to colonise other regions.

In general, the areas of the globe that were most recently colonised incorporate fewer phonemes into the local languages whereas the areas that have hosted modern humans for millennia (particularly sub-Saharan Africa) still use the most phonemes.

This decline in phoneme usage cannot be explained by demographic shifts or other local factors, and it provides strong evidence for an African origin of modern human languages — as well as parallel mechanisms that slowly shaped both genetic and linguistic diversity among humans.

The second study, published in Nature by University of Auckland researchers Professor Russell Gray and Dr Simon Greenhill and their colleagues Michael Dunn and Stephen Levinson at the Max Planck Institute for Psycholinguistics in the Netherlands challenges the idea that the human brain produces universal rules for language.

“The diversity of the world’s language is amazing,” says Professor Gray.

“There are about 7,000 languages spoken today, some with just a dozen contrastive sounds, others with more than 100, some with complex patterns of word formation, others with simple words only, some with the verb at the beginning of the sentence, some in the middle, and some at the end.”

“Our work shows that the claims some linguists have made for a really strong role of the innate structure of the human mind in shaping linguistic variation have been hugely oversold,” he says.

Using computational methods derived from evolutionary biology, Gray and his team analysed the global patterns of word-order evolution. Instead of universal patterns of dependencies in word-order features, they found that each language family had its own evolutionary tendencies.

“When it comes to language evolution, culture trumps cognition,” Gray observes.

A new discovery described by a team of international scientists, including Carnegie Museum of Natural History paleontologist Christopher Beard, suggests that anthropoids — the primate group that includes humans, apes, and monkeys — "colonized" Africa, rather than originally evolving in Africa as has been widely accepted.

According to the paper published in the journal Nature, what is exceptional about these new fossils — discovered at the Dur At-Talah escarpment in central Libya – is the diversity of species present: the site includes three distinct families of anthropoid primates that lived in North Africa at approximately the same time.

This suggests that anthropoids underwent diversification, through evolution, previous to the time of these newly discovered fossils, which date to 39 million years ago. The sudden appearance in the African fossil record of diverse anthropoid families can be answered in one of two ways, the paper’s authors say. It could be the result of a striking gap in the African fossil record prior to this period. This is unlikely to be the case as Northern Africa’s Eocene sites have been well sampled over the past century, and no diversity of anthropoid fossils has yet been discovered that predates the new Libyan specimens. Therefore, the paleontologists suggest, it is more likely that several anthropoid species "colonized" Africa from another continent 39 million years ago — the middle of the Eocene epoch. Since diversification would have occurred over extreme lengths of time, and likely leave fossil evidence, the new fossils combined with previous sampling in North Africa leads the paper’s authors to surmise an Asian origin for anthropoids, as proposed by Beard and his colleagues in earlier work, rather than a gap in the fossil record.

"If our ideas are correct, this early colonization of Africa by anthropoids was a truly pivotal event — one of the key points in our evolutionary history," says Christopher Beard, Curator of Vertebrate Paleontology at Carnegie Museum of Natural History and an author on the paper. "At the time, Africa was an island continent; when these anthropoids appeared, there was nothing on that island that could compete with them. It led to a period of flourishing evolutionary divergence amongst anthropoids, and one of those lineages resulted in humans. If our early anthropoid ancestors had not succeeded in migrating from Asia to Africa, we simply wouldn’t exist."

Beard has done extensive research on anthropoid origins, including his work on the primate Eosimias. His book, The Hunt for the Dawn Monkey, has been critical in positing Asia, not Africa, as the place of origin for anthropoids. The search for information regarding the origins of man’s earliest anthropoid ancestors remains one of the most hotly pursued subjects in paleontology.

"This extraordinary new fossil site in Libya shows us that in the middle Eocene, 39 million years ago, there was a surprising diversity of anthropoids living in Africa, whereas few if any anthropoids are known from Africa before this time," says Beard. "This sudden appearance of such diversity suggests that these anthropoids probably colonized Africa from somewhere else. Without earlier fossil evidence in Africa, we’re currently looking to Asia as the place where these animals first evolved.