The interaction of transitivity features in the sinhala involitive

The Sinhala volitive/involitive contrast is characterized by verb stem and subject case marking alternations, and broadly indicates the volitionality/non-volitionality of the subject, plus other co-varying features. While superficially a high/low transitivity split à la Hopper and Thompson (1980), we argue that the distinction actually emerges from the interaction of just two factors: a realis/irrealis mode contrast relating to expectations of certain event participants and an independent semantic case system (building on Inman 1993). Co-variation of other semantic features – including volitionality – follows directly from their interaction with semantic case and modality. Explaining this transitivity split through the interaction of language-specific elements, our analysis refines recent Optimality Theoretic approaches to transitivity (Malchukov 2005, 2006) by partly obviating the need for separate, transitivity-specific constraints and constraint rankings.