Ferjan Ramírez, NajaSheth, Kaveri2025-08-012025-08-012025Sheth_washington_0250E_28533.pdfhttps://hdl.handle.net/1773/53675Thesis (Ph.D.)--University of Washington, 2025Sociocultural frameworks have emphasized the role that social interactions with caregivers play in scaffolding a child’s cognitive and linguistic development. Given that children may interact with a myriad of people, each participating in social interactions in a variety of ways, this dissertation focuses on how variations in early language input, across different caregivers and contexts, shape opportunities for language development. I utilize naturalistic daylong audio recordings to investigate how these variations occur naturally. Because I use naturalistic daylong audio recordings, I rely on manual annotations for a fine-grained analysis of the input. I also ask how computational tools may help us measure language outcomes, given that manual annotations are time consuming and labor intensive. Chapter 2 observes how caregivers may vary in their language input to young children in the home environment. I look at differences in maternal and paternal language input, shedding light on the differences that may occur in quantity, syntactic, and lexical aspects of parentese as the child develops. Chapter 3 investigates how a foreign language intervention, in a preschool setting, may shape children’s language opportunities in a second language. Chapter 4 turns to our methodological question and I investigate how current technologies perform language identification tasks on speech from very young children who are learning another language. My results demonstrate that language input varies meaningfully, between caregivers or across contexts, in order to create unique learning opportunities for children. However, current technologies are not able to capture this variation yet, and researchers in the field still must rely on manual annotations. This results in a call for more developmentally informed tools in order to capture the rich variety of early input and output across caregivers and contexts.application/pdfen-USnoneLinguisticsLinguisticsThesis