Please join the Linguistics Department on Monday, May 13th at 2 PM in AP&M 4301 for our colloquium. Andrew Garrett (UC Berkeley) will be presenting.
The chronology of Proto-Indo-European: New evidence from computational phylogenetics
This presentation reports on joint work with Will Chang, David Hall, and Chundra Cathcart.
Within Indo-European studies and historical linguistics more broadly, it remains controversial when and where Proto-Indo-European (PIE) was spoken. According to the hypothesis of Renfrew (1987, 1999, 2000, 2001), PIE was spoken in Anatolia and was spread broadly with the diffusion of agriculture. Since the chronology of farming dispersal is understood, on this hypothesis PIE was spoken in the 7th millennium BCE. An alternative hypothesis (Mallory 1989, Anthony 2007, Parpola 2008) is that PIE was spoken in the steppe north of the Black and Caspian Seas between about 4500 and 3500 BCE. According to this “steppe hypothesis”, language spread in Asia and Europe was associated with horse domestication, wheeled transport, and other cultural innovations. The two analyses of PIE origins thus differ in chronology by some 3000 years.
In the last decade this debate has been put on a new footing with research by Gray & Atkinson (2003), Bouckaert et al. (2012), and other associated work by the same authors and their colleagues. In this line of research, computational methods from biological phylogenetics are applied to linguistic data (e.g. basic vocabulary lists) in order to infer phylogeny and chronology. The latter in particular does not rely on the glottochronological assumption of a constant rate of change, but assumes only that rates of change are distributed in a statistically tractable way. Without exception, and using a variety of tools, datasets, and statistical and model assumptions, work along these lines has pointed to the Anatolian chronology for PIE. Most Indo-Europeanists do not accept this chronology, so the results have been controversial and widely reported.
This paper reports on a computational analysis demonstrating that the data actually support the steppe hypothesis. Our approach has been to use methods similar to those of Gray & Atkinson, Bouckaert et al., etc., but to revise the data coding in way that is linguistically more plausible than in previous work. The relevant revisions will be discussed and supported in detail. When linguistically plausible assumptions are made, then it can be shown that a PIE chronology consistent with the steppe hypothesis is favored.