On the origins of passive allomorphy in Cuwabo (Bantu P34)

Cuwabo has two different derivational suffixes to form passive verb stems, i.e. -iw and -uw. Unlike in many other Bantu languages, these suffixes are not phonologically conditioned allomorphs of one single morphological passive marker. They are interchangeable as productive passive markers, but -uw has a broader functional range than -iw. The suffix -uw actually is a ‘quasi-middle’ marker as defined by Dom et al.: it semantically focuses the activity expressed by the verb on one single argument, and it syntactically signals the intransitivity of a given verb stem. In this article, it is shown that -uw in Cuwabo is the regular reflex of the Proto-Bantu intransitive separative suffix *-ʊk whose semi-productive intransitivising function as part of a causative/anticausative alternation was functionally broadened to productive passivisation leading to competition with -iw, the inherited reflex of the Proto-Bantu passive suffix *-ibʊ