This dissertation focuses on the Crow language, an Indigenous language spoken in southern Montana of North America. This dissertation considers three topics in Crow linguistics: documentation, grammar, and history.

In Chapter 3, on documentation, I consider semantic field methodology and argue that fieldworkers who are describing the semantic grammar of a language may wish to consider co-speech gesture as an important resource for conveying abstract grammatical notions. The genesis of this work lies in the lack of previous work that rigorously analyzed the semanticsof modal and aspect marking in Crow that participate in triggering multiple exponence. During the semantic elicitation sessions, I noticed that Jack Real Bird, a collaborator and fluent speaker of Crow, was employing gestures, in addition to his English utterances, to concretize the specific meanings of his Crow utterances. These gestures were not random and not devoid of semantic content; instead, they were meaningful within the situated, interactional setting. This chapter focuses on the aspect markers, -dahku and daachi, whose meanings are not entirely clear. Employing discourse and gesture analysis, I suggest that the former is most appropriately analyzed as an iterative and the latter as a continuative.

In Chapter 4, on grammar, I present an account of the patterns of multiple exponence in Crow within the framework of Distributed Morphology. Under the view that raising and control in Crow are derived via A-movement (Hornstein, 1999), the main generalization is that only unergatives may exhibit multiple-person marking in raising constructions. On the other hand, all verbs show multiple marking of person features in control and causative clauses. The analysis hinges on the crucial assumption that a necessary precondition for the (multiple) occurrences of A-set morphemes is agreement between a probe on Aux and the highest accessible DP argument, such that multiple-person marking is simply the result of pronouncing all copies that bear nominative Case within a single A-movement chain.

In Chapter 5, on history, I investigate the diachrony of multiple exponence in Crow. Although most occurrences of multiple exponence in Crow can be explained by grammaticalization of a lexical verb to a grammatical suffix, cases of multiple exponence that involve modal auxiliaries developed through different pathways. In particular, first I argue that multipleexponence observed across the set of modal auxiliaries originated with the grammaticalization of the motion verb *h ́ıi ‘arrive there’ as a future suffix -ii, retaining its agreement when it grammaticalized. Then, the inflectional future then served as the basis for the formation of modal auxiliaries -iimmaachi ‘will, must’, -iih ‘may, might’, and -iishdaachi ‘should’. Finally, co-occurrence of person agreement on these modal auxiliaries was later ex- tended to another modal -isshi ‘feel like’, for which cognates can be found across all Siouan languages—a distinct case of multiple exponence begetting additional multiple exponence.

Chapter 1 outlines my positionality with regard to this dissertation, Chapter 2 is an introductory chapter that gives an overview of Crow, and a concluding Chapter 6 summarizes.