Systematic Bayesian phylogenetics reveal dialect chain breakup in the Timor-Alor-Pantar language family

This paper refines the subgroupings of the Timor-Alor-Pantar (TAP) family of Papuan languages, using a systematic Bayesian phylogenetics study. While recent work indicates that the TAP family comprises a Timor (T) branch and an Alor Pantar (AP) branch (Holton et al. 2012, Schapper et al. 2017), the internal structure of the AP branch has proven to be challenging. Our Bayesian inference study is based on extensive TAP lexical data from the online LexiRumah database (Kaiping et al. 2019b, Kaiping & Klamer 2018). Systematically comparing different analytical models and tying them back to the historical linguistics, we arrive at a subgrouping structure of the TAP family based on features of the phylogenies shared across the different analyses. Our TAP tree differs from all earlier proposals by inferring the East-Alor subgroup as an early split-off from all other AP languages, instead of the most deeply embedded subgroup inside that branch. The evidences suggests that dialect cluster effects played a major role in the formation of today’s Timor-Alor-Pantar languages.