Posted by: Democratic Thinker | March 21, 2015

Study: Ancestry-constrained phylogenetic analysis supports the Indo-European steppe hypothesis


The Linguistic Society of America provides a pre-print of an article appearing in this month’s Language journal.

The relationships of Indo-European (IE) languages have been studied for over two centuries, but it is still disputed when and where their common ancestor Proto-Indo-European (PIE) was spoken, and how they spread before they first appeared in historical records about 3,700 years ago.


Linguistic Society of America (LSA).


Forthcoming Articles

Language  (Vol. 91, No. 1) March 2015

Ancestry-constrained phylogenetic analysis supports the Indo-European steppe hypothesis

Will Chang, Chundra Cathcart, David Hall and Andrew Garrett, University of California, Berkeley

LSA Language Cover, Vol 91 No 1.

Discussion of Indo-European origins and dispersal focuses on two hypotheses. Qualitative evidence from reconstructed vocabulary and correlations with archaeological data suggest that Indo-European languages originated in the Pontic-Caspian steppe and spread together with cultural innovations associated with pastoralism, beginning c. 6500–5500 BP. An alternative hypothesis, according to which Indo-European languages spread with the diffusion of farming from Anatolia, beginning c. 9500–8000 BP, is supported by statistical phylogenetic and phylogeographic analyses of lexical traits. The time and place of the Indo-European ancestor language therefore remain disputed. Here we present a phylogenetic analysis in which ancestry constraints permit more accurate inference of rates of change, based on observed changes between ancient or medieval languages and their modern descendants, and we show that the result strongly supports the steppe hypothesis. Positing ancestry constraints also reveals that homoplasy is common in lexical traits, contrary to the assumptions of previous work. We show that lexical traits undergo recurrent evolution due to recurring patterns of semantic and morphological change.

Figure 6.—Click for Larger View.

Figure 6. Analysis C3 summary tree. Modern languages with no ancestors in the data set are excluded, but ancestry constraints are not used. There are time constraints on splits. See Fig. 1 caption to interpret other graphical elements.

(Read Pre-print (PDF))

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