Alexei Kassian (Institute of Linguistics of the Russian Academy of Sciences)
[email protected], 21 October, 2014 Linguistic homoplasy and phylogeny reconstruction. The cases of Lezgian and Tsezic languages (North Caucasus) The paper deals with the problem of linguistic homoplasy (parallel or back developments), how it can be detected, what kinds of linguistic homoplasy can be distinguished and what kinds are more deleterious for language phylogeny reconstruction. It is proposed that language phylogeny reconstruction should consist of two main stages. Firstly, a consensus tree, based on high-quality input data elaborated with help of the main phylogenetic methods (such as NJ, Bayesian MCMC, MP), and ancestral character states are to be reconstructed that allow us to reveal a certain amount of homoplastic characters. Secondly, after these homoplastic characters are eliminated from the input matrix, the consensus tree is to be compiled again. It is expected that, after homoplastic optimization, individual problem clades can be better resolved and generally the homoplasy-optimized phylogeny should be more robust than the initially reconstructed tree. The proposed procedure is tested on the 110-item Swadesh wordlists of the Lezgian and Tsezic groups. Lezgian and Tsezic results generally support theoretical expectations. The Minimal lateral network method, currently implemented in the LingPy software, is a helpful tool for linguistic homoplasy detection. 1. How to reveal homoplasy .................................................................................................................................