Dentality areal features and phonological change in northeastern Bantu

A minority of the world's languages appear to have a series of dental (as opposed to alveolar) obstruents. Proto-Bantu does not have such a series, nor do most East African Bantu languages. By contrast, three Bantu languages in northeastern Kenya (the northern Swahili dialects, Pokomo, Elwana) have acquired such a series, which thus merits explanation. There are three mechanisms involved: sounds along with loan vocabulary, (b) a simple phonological shift whereby inherited alveolars moved one place to become dental, and (c) a more complicated shift whereby inherited (pre) palatals bypassed an intervening alveolar series to become dental, a process little reported in the literature. It is hypothesised that these forms of denta1isation took place under historical conditions of contact with neighboring Cushitic communities--not the larger Eastern Cushitic communities of today (Somali, Orma), but rather the ancestral forms of what are now remnant languages, (probably) Southern Cushitic Dahalo and (possible) Eastern Cushitic Aweera. (a) the borrowing of loan 1.