Verb paradigm in Tomo Kan Dogon: interconnections of polypredicative constructions, grammaticalization, and tonology

The paper deals with the grammaticalization problems in Tomo Kan (Dogon family, Niger-Congo) and, in particular, with the diachronic relationship of polypredicative constructions and TAM markers. Dogon languages are characterized by TAM systems that seem to be dia-chronically unstable since markers with a similar range of meanings go back to different lexi-cal sources in different languages of the family. TAM markers are apparently associated with polypredicative constructions, which are very common in Dogon and preserve some of their morphosyntactic properties. At the same time, Dogon languages are characterized by complex tonal changes triggered not only by phonological context but also by the syntactic position of constituents. These tonal changes, frequently referred to as tonosyntax, accompany the formation of polypredicative constructions and other syntactic phenomena. A thorough inves-tigation of Tomo Kan TAM markers shows their tonosyntactic properties to resemble those of polypredicative constructions. Moreover, assuming that tonosyntax of polypredicative con-structions triggers certain tonal contour overlays, one can account for tonal alternations ob-served in TAM forms which would have been left otherwise unexplained. However, the anal-ysis also reveals that at least two classes of TAM forms must be distinguished in Tomo Kan: one of them inherits the tonosyntax of polypredicative constructions while the other does not. A hypothesis is put forward that the latter class has a different source of grammaticalization and is probably associated with verb stem incorporation rather than with polypredication. Methodologically, the paper shows a critical role of tonology in the analysis of grammaticalization processes in tonal languages.