This paper engages longstanding questions regarding how children acquire morphology in polysynthetic languages. It examines the roles of frequency, perceptual salience, and semantic complexity for morphemes in the acquisition of Northern East Cree possessive inflection, where prefixes and suffixes interact to encode possessors. Two studies analyze naturalistic video recordings of one adult and two children. Study 1 describes the frequency, salience, and complexity of possessor-encoding morphemes in the input. Study 2 traces the acquisition of these morphemes in child speech. Results indicate the acquisition of possessor inflection involves a combination of factors whose influences shift over time. Perceptual salience plays a key role in early noun production, but frequency later corresponds more clearly to acquisitional order for high-frequency morphemes. Complexity is hard to isolate from frequency, although neither factor clearly determines acquisitional order for low-frequency morphemes. The paper concludes by considering implications for science and potential applications for Cree communities.

This study presents the first investigation of the development of possessive constructions in Northern East Cree, a polysynthetic language indigenous to Canada. It examines transcripts from naturalistic recording sessions involving one adult and one child, from age 2;01.12 to 3;08.24. Findings reveal that, despite the frequency of possessive inflection in child-directed speech, the child overwhelmingly produces a possessive construction that circumvents this morphology. This construction, named here the equational possessive strategy (EPS), is largely undescribed in existing literature but is the primary mechanism for the child to express possession. These findings have potential implications for the cross-linguistic acquisition of possessive morphology and the connections between child-directed speech and child language production.