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Title of Dissertation : Grammatical complexity, language contact, and morphosyntactic change in Nheengatu

Nheengatu is an indigenous language of South America spoken predominantly in the Upper Rio Negro region of the Amazon rainforest. It is the modern descendant of Old Tupi, a language that was spoken along much of the Brazilian coastline when Europeans first arrived into the Americas in the late 15th century. When the Portuguese began colonizing Brazil, Old Tupi was initially adopted as a língua geral, or general language, to facilitate communication between people of varied ethnolinguistic backgrounds. The language is thought to have changed dramatically as a result of widespread non-native acquisition and later attrition as its speakers began to shift to Portuguese. My dissertation looks in detail at several of these changes from the perspectives of grammatical complexity and language contact, and presents analyses of how and why they occurred by drawing on a usage-based and evolutionary theoretical framework.