This paper investigates correlations between theme vowels and argument structure in Serbo-Croatian. Specifically, we focus on two different theme vowels, -i- and -ova-, isolating ‘minimal pairs’, that is cases where the same base combines with the two theme vowels to derive different verbs. Starting from two online corpora of Serbo-Croatian, we created a comprehensive list of -i-/-ova- minimal pairs. For all pairs in the list whose both members were attested at least 50 times in the corpora, we randomly selected 50 tokens per verb and annotated them for transitivity. A statistical comparison of -i- and -ova- verbs according to the proportions of transitive uses was carried out. The findings show that -i- verbs are much more likely to be used transitively than -ova- verbs. This finding corroborates the view that theme vowels are associated with argument structure properties and challenges the idea that they are universally ‘ornamental’ pieces of morphology without syntactic/semantic import. Based on these and supplementary (non-corpus) data, we claim that -i- derives transitives and unaccusatives, while -ova- derives unergatives. We propose a model couched in Distributed Morphology whereby these two theme vowels are treated as instantiations of different ‘flavors of v’.
