Language tree rooted in Turkey

Evolutionary ideas give farmers credit for Indo-European tongues.

27 November 2003

A family tree of Indo-European languages suggests they began to spread and split about 9,000 years ago. The finding hints that farmers in what is now Turkey drove the language boom - and not later Siberian horsemen, as some linguists reckon.

Russell Gray and Quentin Atkinson, of the University of Auckland in New Zealand use the rate at which words change to gauge the age of the tree's roots - just as biologists estimate a species' age from the rate of gene mutations. The differences between words, or DNA sequences, are a measure of how closely languages, or species, are related.

Gray and Atkinson analysed 87 languages from Irish to Afghan. Rather than compare entire dictionaries, they used a list of 200 words that are found in all cultures, such as 'I', 'hunt' and 'sky'. Words are better understood than grammar as a guide to language history; the same sentence structure can arise independently in different tongues.

The resulting tree matches many existing ideas about language development. Spanish and Portuguese come out as sisters, for example - both are cousins to German, and Hindi is a more distant relation to all three.

All other Indo-European languages split off from Hittite, the oldest recorded member of the group, between 8,000 and 10,000 years ago, the pair calculates¹.

Around this time, farming techniques began to spread out of Anatolia - now Turkey - across Europe and Asia, archaeological evidence shows. The farmers themselves may have moved, or natives may have adopted words along with agricultural technology.

The conclusion will be controversial, as there is no consensus on where Indo-European languages came from. Some linguists believe that Kurgan horsemen carried them out of central Asia 6,000 years ago. "No matter how we [changed] the analysis or assumptions, we couldn't get a date of around 6,000 years," says Gray.

"This kind of study is exactly what linguistics needs," says April McMahon, who studies the history of languages at the University of Sheffield, UK. It shows how ideas about language evolution can be tested, she says: "Linguists have always been good at coming up with bold hypotheses, but they haven't been terribly good at testing them."

But the technique is still fraught with difficulties, McMahon warns. There is lots of word-swapping within language groups. English took 'skirt' from the Vikings, for example, but 'shirt' is original. Linguists must separate the shared from the swapped, as any error will affect later studies.

The Kurgan might not be out of the picture entirely, says McMahon - they may have triggered a later wave of languages. "This isn't going to knock the debate on the head," she says.

Biology and linguistics can learn a lot from each other, comments geneticist David Searls of GlaxoSmithKline Pharmaceuticals, based in King of Prussia, Pennsylvania. "There may be some fundamental principles of evolution of complex systems, such as languages and organisms," he says.

Indo-European Languages Originated in Anatolia, Research Suggests

ScienceDaily (Aug. 23, 2012) — The Indo-European languages belong to one of the widest spread language families of the world. For the last two millenia, many of these languages have been written, and their history is relatively clear. But controversy remains about the time and place of the origins of the family. A large international team, including MPI researcher Michael Dunn, reports the results of an innovative Bayesian phylogeographic analysis of Indo-European linguistic and spatial data. Their paper appears this week in Science.

The majority view in historical linguistics is that the homeland of Indo-European is located in the Pontic steppes (present day Ukraine) around 6,000 years ago. The evidence for this comes from linguistic paleontology: in particular, certain words to do with the technology of wheeled vehicles are arguably present across all the branches of the Indo-European family; and archaeology tells us that wheeled vehicles arose no earlier than this date. The minority view links the origins of Indo-European with the spread of farming from Anatolia 8,000 to 9,500 years ago.

Lexicons combined with dispersal of speakers

The minority view is decisively supported by the present analysis in this week's Science. This analysis combines a model of the evolution of the lexicons of individual languages with an explicit spatial model of the dispersal of the speakers of those languages. Known events in the past (the date of attestation dead languages, as well as events which can be fixed from archaeology or the historical record) are used to calibrate the inferred family tree against time.

Importance of phylogenetic trees

The lexical data used in this analysis come from the Indo-European Lexical Cognacy Database (IELex). This database has been developed in MPI's Evolutionary Processes in Language and Culture group, and provides a large, high-quality collection of language data suitable for phylogenetic analysis. Beyond the intrinsic interest of uncovering the history of language families and their speakers, phylogenetic trees are crucially important for understanding evolution and diversity in many human sciences, from syntax and semantics to social structure.

Story Source:

The above story is reprinted from materials provided by Radboud University Nijmegen, via AlphaGalileo.

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Journal Reference:

R. Bouckaert, P. Lemey, M. Dunn, S. J. Greenhill, A. V. Alekseyenko, A. J. Drummond, R. D. Gray, M. A. Suchard, Q. D. Atkinson. Mapping the Origins and Expansion of the Indo-European Language Family. Science, 2012; 337 (6097): 957 DOI: 10.1126/science.1219669

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