|The dissertation is a preliminary grammatical description of the language spoken by the Apinajé, one of the Northern Jê peoples of Central Brazil. It discusses the core facts about Apinajé phonology, morphology and syntax from a functional-typlogical perspective, and provides three appendices: selected maps, a sample collection of texts and a preliminary dictionary. The phonological analysis proposes an alternative interpretation for the inventory of phonemes as comparedto earlier analyses, pointing to phonemic distinctions not previously noted, which might lead to interesting findings regarding the historical development of the language. Apinajé morphemes are typically monosyllabic and the language makes ample use of function words for the expression of grammatical categories, properties that are characteristic of analytic languages. Nonetheless, Apinajé morphology is more complex than it might seem at first, especially with respect to the major lexical categories of the language: Nouns, Verbs and Postpositions. These word classes, especially Nouns and Verbs, are characterized morphologically by the presence of formatives, which are recurrent morphs that are either semantically empty or of elusive meaning, but which subcategorize words in formal or semantic terms. The categories of nonfiniteness, person, and syntactic constituency constitute the core of inflectional morphology, the latter applying to nouns and postpositions, as well as verbs. Verbs are subcategorized morphosyntactically into transitives, intransitives and descriptives, displaying a split intransitivity system with respect to verbal person-marking. Word order is predominantly SOV. Syntactically complex constructions include verb serialization and clause subordination, with ergative case-marking a characteristic of subordinate clauses.