Abstract
Part of language development necessarily involves connecting sensory inputwith linguistic units. We asked whether visual input in particular was differ-entially relevant for learning words and building grammar. While substan-tial prior work (e.g. Bates & Goodman, 1997) confirms a tight link betweengrammar and the lexicon, there could in principle be different degrees ofreliance on a visual referential world across them. To begin to tackle thislarge question, we examined the productive morphosyntax skills of youngblind children (N=28, 14-55mo.), each matched to a sighted child of thesame productive vocabulary size, based on a parent-reported vocabulary andearly grammar checklist. We asked whether blind children’s morphosyntacticskills were similar, advanced, or delayed relative to sighted vocabulary-size-matched peers. We found no differences between blind and sighted childrenacross 6 morphosyntax measures. Blind children did show a delay in produc-tive morphosyntax skills relative to sighted children, and this delay (roughly9 months) was statistically longer than the delay reported for spoken vo-cabulary in this same group (Campbell, Casillas, & Bergelson, 2024). Wealso found that both age and vocabulary strongly predicted morphosyntaxscores for sighted children, but only vocabulary size (and not age) robustlypredicted morphosyntax for blind children. These results extend seminalresearch in early language development in blind and sighted children (e.g.Landau & Gleitman, 1985), highlighting close vocabulary to syntax links inearly childhood across groups, and supporting the idea that vision does notcontribute separably to either facet of language development.