The Roots of Language

The biologists' latest foray onto the linguists' turf is a reconstruction of the Indo-European family of languages by Dr. Russell D. Gray, an evolutionary biologist at the University of Auckland in New Zealand.

The family includes extinct languages like Hittite of ancient Turkey, and Tokharian, once spoken in Central Asia, as well as the Indian languages and Iranian in one major branch and all European languages except Basque in another.

Dr. Gray's results, published in November in Nature with his colleague Quentin Atkinson, have major implications, if correct, for archaeology as well as for linguistics. The shape of his tree is unsurprising — it arranges the Indo-European languages in much the same way as linguists do, using conventional methods of comparison. But the dates he puts on the tree are radically older.

Dr. Gray's calculations show that the ancestral tongue known as proto-Indo-European existed some 8,700 years ago (give or take 1,200 years), making it considerably older than linguists have assumed is likely.

Some researchers, following the lead of Dr. Marija Gimbutas, who died in 1994, believe that the Indo-European languages were spread by warriors moving from their homeland in the Russian steppes, north of the Black and Caspian Seas, some time after 6,000 years ago.

A rival theory, proposed by Dr. Colin Renfrew of the University of Cambridge, holds that the Indo-Europeans were the first farmers who lived in ancient Turkey and that their language expanded not by conquest but with the spread of agriculture some 10,000 to 8,000 years ago.

Dr. Gray's date, if accepted, would support the Renfrew position.

If the biologists' methods can date languages that existed 9,000 years ago, how much further back can they probe?

"Words exist that can in principle resolve 20,000-year-old linguistic relationships," Dr. Pagel of Reading wrote in a recent symposium volume, "Time Depth in Historical Linguistics," adding that "words that can resolve even deeper linguistic relationships are not out of the question."

Many linguists believe that once two languages have drifted so far apart that they share only 5 percent or so of their vocabulary, chance resemblances will overwhelm the true ones, setting a firm limit on how far back their ancestry can be traced.

Chart here or here.