Inheritance and contact in the genesis of Gisamba (Bantu, L12a, DRC): A diachronic phonological approach

Gisamba (ISO 639-3: smx) is a nearly undocumented and undescribed as well as highly endangered Bantu language spoken in the Kwilu and Kwango provinces of the Democratic Republic of the Congo (DRC). It belongs to the Kikongo Language Cluster (KLC), a discrete subclade of the West-Coastal Bantu (WCB) branch of the Bantu language family. Within the KLC, Gisamba forms a distinct subgroup called “Kikongoid” together with Kiyaka, Kisuku and Kihungan, which are also spoken in the Kwilu and Kwango provinces of the DRC. In this article, we show how both divergence as part of WCB and the KLC and convergence through contact with neighboring WCB and South-West Bantu (SWB) languages contributed to the genesis of Gisamba as spoken today. For this purpose, we provide a synchronic and diachronic account of the phonology of Gisamba. Data used in this article stem from original fieldwork which the first author conducted in 2017 in the village of Kimafu. Some of the diachronic sound changes confirm Gisamba’s affiliation to WCB, the KLC and Kikongoid. Others show that Gisamba’s synchronic phonology cannot be accounted for as being only the result of vertical transmission through inheritance, but must be the outcome of horizontal transmission through space. This is well in line with the fact that Gisamba is currently endangered and that, historically speaking, its speech communities have been scattered in the Kwilu and Kwango provinces of the DRC where they are surrounded by much larger WCB and SWB speech communities.