Areal diffusion and the limits of grammaticalization

Intensive contact brings about diffusion of grammatical categories. Grammaticalization of lexical items is one of the mechanisms at play as languages converge and new categories develop. In a situation of intensive contact-induced change, the forms to be grammaticalized, and semantic changes involved, may turn out to be somewhat unexpected, forcing us to reconsider potential constraints on grammaticalization. We focus on a number of instances of hitherto undescribed grammaticalization paths in the languages of the Vaupés River Basin linguistic area in northwest Amazonia (especially Tariana, the only extant Arawak language), and then discuss further examples of typologically unusual instances of grammaticalization in Amazonian languages.