Project Summary One of the most highly debated questions for caregivers of deaf and hard of hearing (DHH) children and the professionals who serve them is that of which “communication mode” to use. Will the child have higher language skills if they are taught American Sign Language (ASL) or spoken English or both? Caregivers face this decision when their child is diagnosed, their hearing status changes, and they show language difficulties. Professional guidance is hampered by contradictory perspectives and limited evidence on how communication mode affects long-term outcomes. Limited data for language growth expectations make it unclear whether a DHH child is making sufficient progress to achieve age expectations. The relevant data are spotty, especially for ASL, and often restricted to a subpopulation, single measure, and/or short time span. As a result, DHH children are at risk for receiving ineffective intervention. To provide vital empirical guidance on the impact of exposure to ASL and/or English and whether children are making expected progress, we first need to characterize the language development of DHH children who vary in their access to signed versus spoken languages and developmental histories. Currently, no such natural history data exists, which is a major roadblock. Our team will collaborate with the Kansas Language Assessment Program – DHH to analyze data from one of the largest sources of ASL and English development data currently available. We create growth curves of expressive ASL and English skills of 250 DHH children (0–8 years old) from this population-based sample. These models will provide novel information regarding the natural history of language development in DHH children, which is critical for making intervention decisions and improving language outcomes (Aim 1). Without knowledge of expected developmental trajectories and which lead to age-expected language skills, professionals currently risk providing suboptimal or even detrimental amounts or types of intervention. We also initiate a programmatic line of research to identify sources of variation in language outcomes across DHH children and then address malleable factors to improve outcomes. In this proposed project, we focus on elucidating the effects of language access on language growth because our sample is uniquely positioned to address this far-reaching and longstanding question (Aims 2 and 3). Importantly, the participants are exposed to varying amounts of ASL and English and such data are collected systematically. We not only evaluate the influence of language access on ASL and English growth, but also its predictive value when traditional communication mode (i.e., "sign" versus "oral”) is already accounted for (Aim 3). This study provides a robust foundation for analyzing an enduring population-based sample with enormous potential. Future studies will take advantage of the growing sample to predict longer-term outcomes and intervene on malleable factors to improve outcomes. Improving outcomes is critical because of the persistent language deficits for DHH individuals and long-term negative academic, vocational, and social implications.

Project Narrative This project addresses one of the most highly debated questions for caregivers of deaf and hard of hearing (DHH) children: whether to use sign language, spoken language, or both. We aim to leverage a large, prospective, population-based sample of DHH children to identify indicators for expressive language growth needed to “catch up” to peers with typical hearing and to reveal the influence of access to American Sign Language and spoken English on language growth. This knowledge is critical for improving language, academic, vocational, and social outcomes for DHH children, a historically under researched group.