Word Learning and Vocabulary Development in Blind Children

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Project Summary A lack of visual experience may affect language development in the domains of word learning and vocabulary development in ways that necessitate specific instructional approaches and interventions for blind children. Compared to sighted children, blind children may learn more words from speech because they do not casually perceive writing in their environment and often experience reading delays. They may also learn fewer words from direct perceptual experience because they cannot acquire the meanings of words by perceiving their ref- erents visually. Cumulatively, these word learning differences may affect the trajectory of vocabulary develop- ment in early and middle childhood. An improved understanding of vocabulary development could improve ed- ucation for this underserved population. Unfortunately, word learning and vocabulary are understudied within the area of blind children’s language development. This observational analytic study employing a cross-sec- tional design directly compares self-reported modes (perceptual or linguistic) and channels (spoken or written) of word learning for individual words in blind and sighted children. It also compares their trajectories of vocabu- lary development from age 5 to 12. Specific aims are 1) Determine whether vocabulary development in blind children is delayed relative to sighted children; 2) Examine whether mode and channel of word learning in blind children differ from those in sighted children; and 3) Present a dataset of age-of-acquisition (AoA), mode-of- acquisition (MoA), and channel-of-acquisition (CoA) norms for future use in research. The approach is innova- tive because objective age-of-acquisition norms (obtained from children themselves rather than subjective adult estimates) are more reliable and valid than subjective norms and are exceptionally rare. The verbal ad- ministration of tasks that are typically administered visually will make them accessible not only to blind children, but to any child with a reading or learning disability. Finally, the virtual approach to data collection will allow the researchers to reach more individuals from a population that is historically difficult to study. The project is an instrumental part of the PI’s long-term goal of understanding how vocabulary develops without sight and apply- ing this understanding to improve educational strategies and outcomes in blind children.