The mistery of the origin of Australian languages

Methods used in evolutionary biology show how people spread across the continent, giving birth to new languages

A myth in Australia says that a woman named Warramurrungunji emerged from the sea and that she created children as she moved across the landscape. Warramurrungunji told each child to speak an specific language. This myth has more reason than it seems, in the sense that the peopling and language origins of Australia are closely entwined. Researchers have long puzzled over both. When Europeans colonized Australia 250 years ago, the continent was home to an estimated half-million to 2 million people who were organized into about 700 different grops and spoke at least 300 languages.

Linguits have struggled to work out how these languages were related and when they emerged, but unfortunately each one was spoken by relatively few people and many of them vanished before they could be studied. In recent years researchers have begun to unravel the Australian linguistic puzzle, and this week the approach takes a major step forward, with a combined genetic and linguistic study of the largest Australian language family, led by evolutionary geneticist Eske Willerslev of the University of Copenhagen, and published in this week´s issue of Nature.

Back in 1963, linguist Ken Hale identified what he considered to be a new Australian language family. He named it Pama-Nyungan. If Hale was right, then Pama-Nyungan, with more than 200 identified languages, would be one of the world´s largest language family. Linguists had long noted that most languages across Australia draw from the same set of sounds, and that their verbs and pronouns share similar patterns of construction. Given these similarities, linguists would expect the languages to share many cognates, or words derived from a common ancestor, but the reality is that Australian languages have few cognates.

Some suggested that the Pama-Nyungan family entered the continent in a separate migration, whereas others argued that it split off from other Aboriginal languages only a few thousand years ago. Now, a new generation of researchers is attacking the problem; they are using computers to sort giant databases of cognates and generate millions of possible family trees based on assumptions about how quickly languages split. The initial work found that Pama-Nyungan has a deep family tree with four major divisions tried to the southeastern, northern, central, and western regions of the continent. Claire Bowern of Yale University is a pioneer of the approach and co-autor of the new study.

For the study published in Nature, Bowern drew from an expanded database of 800,000 words, which contains 80% of all Australian language data ever published, and looked at cognates from 28 languages across 200 meanings. Then she compared her tree with genomic data from Willerslev´s new survey, in which complete genomes from 83 Aboriginal Australians as well as 25 Highland Papuans were sequenced. This data was combined with published genomes and they conclude that Papuan and Aboriginal Australian ancestors diverged perhaps 37,000 years ago. The genetic analysis also found no evidence of multiple migrations into Australia, suggesting that Pama-Nyungan languages must have diversified on the continent. To the researcher´s amazement, the genetic pattern mirrored the linguistic one. Both types of data also show that the population expanded from the northeast to the southwest.

However, not all linguists embrace Bowern´s method or results. Linguist R.M.W. Dixon of James Cook University in Australia, in his view the best model of Pama-Nyungan family relations is the parallel tines of a rake, not a tree, and the many similarities in these languages can mainly be accounted for by diffusion. Other linguists argue that the computational models, built for genes that can only be inherited, deal poorly with languages that spread by diffusion.

As a curious fact, the Aboriginal stories suggest as much, describing the birth of languages much the way Bowern thinks it happened. In 2004, Evans recorded an Iwaidja speaker, Brian Yambikbik, explaining how his language might be related to the one spoken on distant islands. "We used to speak the same language as them, but then the sea came up and we drifted apart, and now our languages are different".



References

- Erard, Michael. 2016. Solving Australia´s language puzzle. Science. Vol 353, Issue 6306,
  pp. 1357-1359. DOI: 10.1126/science.353.6306.1357
  Michael Erard is the author of Babel No More: The Search for the World´s Most Extraordinary
  Language Learners.