Effects of input quality on ASL vocabulary acquisition in deaf children

Boston University (Charles River Campus), Boston MA

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Abstract

This research project aims to document the factors that shape the trajectory of language acquisition among late signers, children who are learning a sign language and have early exposure to a rich language environment but exhibit delays in early vocabulary development. Because there have not been assessments to enable identification of late signers until recently, there are no studies documenting late signing. Under the parent grant, we developed an assessment of early vocabulary, and administered it to a large number of deaf children learning a sign language. From the data collected under the parent grant, we identified 51 deaf children with early exposure to sign language who nevertheless had delayed early vocabularies. The project has three specific aims: (1) to determine whether late signers go on to also have delays in ASL morphosyntax and vocabulary, and identify possible socio-environmental predictors of trajectories among late signers, (2) to compare effects of phonological neighborhood density in late and typically-developing signers, and (3) to use spontaneous language samples to create in-depth receptive and expressive language profiles to document the developmental sequelae of late signing. The proposed research is innovative in two ways. First, it seeks to disentangle the effects of modality-specific characteristics of late talking from those that are language-general or cognitive by documenting patterns of late signing. Second, this work will be the first empirical study providing insight to families and providers about sign language delays that cannot be attributed to delayed language exposure.