Evidence against unidirectionality in the emergence of middle voice systems

Abstract Middle voice systems are characterized by the distribution of a middle marker over two macro-classes of verbs: oppositional and non-oppositional verbs. In diachronic studies, it has been proposed that the historical link between the two groups is unidirectional, with middle marking spreading from oppositional to non-oppositional verbs. In this paper, we challenge this assumption and discuss two case studies, one from Anatolian and one from Paman languages that show the opposite development, that is, from non-oppositional to oppositional. In both cases, we argue, constructions that originally had a lexically determined distribution develop grammatical functions connected with valency reduction.