This study compares the lexical composition of 118 children with autism spectrum disorder (ASD) aged 12 to 84 months with 4626 vocabulary-matched typically developing toddlers with and without language delay, aged 8 to 30 months. Children with ASD and late talkers showed a weaker noun bias. Additionally, differences were identified in the proportion of nouns and verbs, and in the semantic categories of animals, toys, household items and vehicles. Most differences appear to reflect the extent of the age differences between the groups. However, children with ASD produced fewer high-social verbs than typical talkers and late talkers, a difference that might be associated with ASD features. In sum, our findings identified areas of overlap and distinction across the developing lexical profiles.

Children with autism spectrum disorder often have significant language delays. But do they learn language differently than neurotypical toddlers? We compared the lexical skills of 64 preverbal and minimally verbal children with autism spectrum disorder to 461 vocabulary-size-matched typically developing toddlers. We also examined social features of verb knowledge using a novel collection of social ratings. Children with autism spectrum disorder produced proportionally more verbs than typically developing toddlers. Children with autism spectrum disorder produced proportionally more action and food words, while typically developing toddlers produced proportionally more animal, people words, and animal sounds and sound effects. Children with autism spectrum disorder also produced “mommy” and “daddy” at lower rates. We discuss how these differences may reflect an association between lexical development and weaknesses in social communication. Lay abstract Although preverbal and minimally verbal children with autism spectrum disorder represent a significant portion of the autism spectrum disorder population, we have a limited understanding of and characterization of them. Although it is a given that their lexical profiles contain fewer words, it is important to determine whether (a) the words preverbal and minimally verbal children with autism spectrum disorder produce are similar to the first words typically developing children produce or (b) there are unique features of the limited words that preverbal and minimally verbal children with autism spectrum disorder produce. The current study compared the early word profiles of preverbal and minimally verbal children with autism spectrum disorder to vocabulary-matched typically developing toddlers. Children with autism spectrum disorder produced proportionally more verbs than typically developing toddlers. Also, children with autism spectrum disorder produced proportionally more action and food words, while typically developing toddlers produced proportionally more animal words, animal sounds and sound effects, and people words. Children with autism spectrum disorder also produced “mommy” and “daddy” at lower rates. Our findings identified several areas of overlap in early word learning; however, our findings also point to differences that may be connected to core weaknesses in social communication (i.e. people words). The findings highlight words and categories that could serve as useful targets for communication intervention with preverbal and minimally verbal children with autism spectrum disorder.

This study investigates the influence of semantic maturation on early lexical development by examining the impact of contextual diversity-known to influence semantic development-on word promotion from receptive to productive vocabularies (i.e., comprehension-expression gap). Study 1 compares the vocabularies of 3685 American-English-speaking typical talkers (TTs) and late talkers (LTs; 16-30 months old; 1257 females, 1021 gender unknown; ethnicity unknown; data downloaded in 2018) and finds that LTs, with a longer preverbal phase, produced nouns with lower contextual diversity (R 2 = .80), but verbs with higher contextual diversity (R 2 = .13). Study 2 compares computational network growth models of semantic maturation and finds that verbs require more semantic maturation than nouns, and TTs produce words that are more semantically mature than LTs.