The internal syntax of Shona class prefixes

•Shona noun-class prefixes associate to one of four syntactic positions.•As sortal heads for mass nouns, they associate to Nominal Inner Aspect.•As number-marking heads for count nouns, they associate to Nominal Inner Aspect.•AS expressives, they associate to a dedicated Evaluative position.•As honorifics, they associate to D. Shona (Southern Bantu, Guthrie Zone S10) gender/noun-class prefixes display massive multi-functionality, with concomitant semantic heterogeneity. We argue that this pervasive multi-functionality is a consequence of the pre-syntactic association of Saussurean sound-meaning correspondences and that it reflects the possibility of a prefix associating to distinct syntactic positions, with predictable semantic differences. Using the model of Interface Syntax, we claim that Shona noun-class prefixes associate to one of four syntactic positions: to Nominal Inner Aspect as sortal heads for mass nouns; to Nominal Outer Aspect as number-marking heads for count nouns; to a dedicated Evaluative position as expressives; to D as honorifics. The analysis provides a structural basis of the count/mass contrast, correctly predicts the distribution of substitutive and additive number-marking, accounts for the difference between descriptive and evaluative noun-class prefixes, and derives the existence of alliterative (concordial) agreement.