Environmental factors affect the evolution of linguistic subgroups in Borneo

Abstract

Abstract This study investigates the relatedness and history of the Austronesian languages of Borneo, which is the third largest island in the world and home to significant linguistic diversity. We apply Bayesian phylogenetic dating methods to lexical cognate data based on four historical calibration points to infer a dated phylogeny of 87 languages. The inferred tree topology agrees with the mid and lower-level subgrouping proposals based on the classical comparative method, but suggests a different higher-level organization. The root age of the dated tree is shallower than the archaeological estimates but agrees with a hypothesis of a past linguistic leveling event. The inferred homelands of the major linguistic subgroups from a Bayesian phylogeographic analysis agree with the homeland proposals from archaeology and linguistics. The inferred homelands for four of the eight subgroups support the riverine homeland hypothesis whereby the major linguistic subgroups developed initially in communities situated along Borneo’s major rivers.