This study examined patterns of verbal responsiveness in parents of toddlers (M[subscript age] = 20 months) later identified with autism (n = 121), developmental delay (n = 46), or typical development (n = 44) during an hourlong home observation. Parent verbal responsiveness (PVR) was compared using MANOVA across groups and by child expressive language phase. Multiple regression analyses controlling for child age and maternal education were employed to examine the extent to which PVR predicted variance in concurrent child social communication and prospective language skills. Parents provided synchronous responses approximately 90% of the time. Parents of children with autism and developmental delay used smaller proportions of responses that added linguistic information (i.e., expansions and follow-in directives for language) than those of children with typical development. Parents of children in the preverbal phase were more likely, on average, to affirm their children's acts of intentional communication or provide a follow-in directive for action that did not necessitate a verbal response than to expand or elicit language. Regression results indicated that parental use of expansions and follow-in directives for language made significant contributions to child language outcomes. The patterns we observed may reflect parents' attunement to their child's developmental level. Responsiveness to a child's focus of attention is vital in the earlier stages of language learning; however, results point to the potential importance of parental expansions and follow-in directives for promoting language development across groups in this sample. Directions for intervention research targeting PVR and language skills in toddlers with autism and developmental delays are discussed.