Yeyi: A Phylogenetic Loner in Eastern Bantu

While major advances in the subclassification of Bantu languages have been made thanks to comprehensive, lexicon-based classifications, there are still several important uncertainties obscuring not only the diachronic linguistic processes that gave rise to Bantu diversification, but also the population dynamics of ancestral Bantu speakers underlying them. In this paper, we address one of these persisting mysteries of Bantu genealogy, i.e., the unclassified Yeyi (R41) language of southern Africa. While the Bantu origin of Yeyi is straightforward and undisputed, its closest relatives are unknown, as is the major Bantu branch to which it belongs. We use a lexicon-based, Bayesian phylogenetic approach, comparing Yeyi to languages of the wider geographic region, including even more far-flung languages that have previously been hypothesized to bear a close relationship to Yeyi. The resultant linguistic phylogeny shows that Yeyi is part of the Wider Eastern Bantu branch as its own clade with Narrow Eastern Bantu languages as its closest relatives and none of its nearest neighbors. We argue that this relatively isolated position of Yeyi within Eastern Bantu suggests an early migration into southern Africa from the putative Wider Eastern Bantu homeland, which was followed by the loss of Yeyi’s putative earlier sister languages, presumably through a shift to Bantu languages spoken by more recent migrants.