Language exposure is key: critical factors shaping bilingual language outcomes in deaf children with deaf and hearing...

To date, deaf children with deaf parents have been assumed to experience "typical" first language acquisition while deaf children from hearing families have often been excluded from research due to limited language exposure in early life. The present study eschews these assumptions and examines language development across these two populations asking whether the use of a signed language at home, the use of a signed language at school, and the family's socioeconomic status or education level can predict deaf children's fluency in American Sign Language (ASL) and English. Language and familial background data were collected from 96 preschoolers (age: 5 years) and 58 middle schoolers (age range: 11-15 years) in the United States. Deaf children of deaf parents reached higher proficiency in both ASL and English than those from hearing families when compared as groups, but there was considerable overlap in language proficiency between the two groups which was associated with the language environments in children's homes for preschoolers and children's schools for middle schoolers. Socioeconomic status and parent education were associated with English proficiency for deaf children of hearing parents, and with ASL proficiency for deaf children of deaf parents.