Lexical and grammatical skills in toddlers on the autism spectrum compared to late talking toddlers.

This study compared language development in 30-month-old toddlers on the autism spectrum and 25- month-old late talking toddlers without autism. Groups were matched on overall productive vocabulary (and nonverbal cognition was controlled) in order to compare language acquisition patterns related to vocabulary composition and early lexical–grammatical relationships. Findings revealed that semantic categories of words— including psychological state terms—used by toddlers on the autism spectrum were very similar to those of late talkers. Both groups were equivalent with respect to grammatical complexity and proportion of toddlers combining words, though late talkers displayed a relatively stronger association between lexical–grammatical abilities. These tentative findings are consistent with a dimensional account of early, core linguistic abilities across different populations of children with language delay.