Purpose: The goal of this work was to examine the semantic and syntactic properties of the vocabularies of autistic and non-autistic infants and toddlers to see if children in these two groups know different kinds of words. We focused on both receptive and expressive vocabularies. For expressive vocabulary, we looked only at the "active"…

Background and aims: Nongenerative speech is the rote repetition of words or phrases heard from others or oneself. The most common manifestations of nongenerative speech are immediate and delayed echolalia, which are a well-attested clinical feature and a salient aspect of atypical language use in autism. However, there are no current estimates of…

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…

Purpose: Several studies have reported that "useful speech" at 5 years of age predicts outcomes in individuals with autism spectrum disorder (ASD), but this skill has been vaguely defined. This study investigates which specific aspects of expressive language in children with ASD best predict adult language and communication outcomes.…

Background: Fragile X syndrome (FXS) and Down syndrome (DS) are the two leading genetic causes of intellectual disability, and FXS is the most common known genetic condition associated with autism. Both FXS and DS are associated with significant language impairment, but little is known about expressive language across domains over time or the role…