Date of Completion


Embargo Period



Language Acquisition, Language input, Sign language, Morphology, Deaf, Emerging language, Nicaraguan Sign Language, Heritage language, Spatial grammar, Peer interaction

Major Advisor

Marie Coppola

Associate Advisor

Letitia Naigles

Associate Advisor

Jennie E. Pyers

Field of Study



Doctor of Philosophy

Open Access

Open Access


Individual children regularize inconsistent language input; many consider this the driving force for language change and emergence. Prior work on Nicaraguan Sign Language found that child learners, created morphological structures that had not existed previously. First-Cohort signers produced spatial modulations inconsistently, both within and across individuals. However, younger Second-Cohort signers who received this inconsistent input produced spatial modulations consistently, innovating morphological structure that had not previously existed in the grammar. Second-Cohort signers benefited from both older-to-younger language learning and peer-to-peer interactions, obscuring the contributions of each. This dissertation disentangles these factors by exploring a sociolinguistic context in which children receive inconsistent linguistic input and also lack linguistic peers: the hearing children of First-Cohort signers. Three studies investigated participants’ signed productions, interpretations of others’ productions, and non-linguistic encoding of spatial events. Results show that (1) individual children can regularize inconsistent input without the benefit of linguistic peers; however, (2) the unique sociocommunicative situation faced by Coda children drives them to regularize in unpredicted ways. They produced unrotated layouts more often than the First-Cohort, despite the strong preference of Second-Cohort signers for rotated layouts. Codas interpreted others’ spatial modulations flexibly, a potential consequence of the lack of a peer language network. These results resonate with findings regarding heritage language learners, whose lack of linguistic peers limits their acquisition of their parents’ native language. These findings have important implications for Deaf children in mainstreamed educational settings, whose sign language input comes primarily from non-fluent adult signers, and who rarely have signing linguistic peers.