Many children with autism spectrum disorders (ASD) acquire a sizeable lexicon. However, these children also seem to understand and/or store the meanings of words differently from typically developing children. One of the mechanisms that helps typically developing children learn novel words is the shape bias, in which the referent of a noun is mapped onto the shape of an object, rather than onto its color, texture, or size. We hypothesized that children with Autistic Disorder would show reduced or absent shape bias. Using the Intermodal Preferential Looking Paradigm (IPL), we compared the performance of young children with ASD and typically developing children (TYP), across four time points, in their use of shape bias. Neither group showed a shape bias at Visit 1, when half of the children in both groups produced fewer than 50 count nouns. Only the TYP group showed a shape bias at Visits 2, 3, and 4. According to growth curve analyses, the rate of increase in the shape bias scores over time was significant for the TYP children. The fact that the TYP group showed a shape bias at 24 months of age, whereas children with ASD did not demonstrate a shape bias despite a sizeable vocabulary, supports a dissociation between vocabulary size and principles governing acquisition in ASD children from early in language development.

Although children with ASD show significant variation in language skills, research on what type(s) of language profiles they demonstrate has been limited. Using growth-curve analyses, we investigated how different groups of young children with ASD show increases in the size of their lexicon, morpho-syntactic production as measured by Brown’s 14 grammatical morphemes, and wh-question complexity, compared to TD children, across six time points. Children with ASD who had higher verbal skills were comparable to TD children on most language measures, whereas the children with ASD who had low verbal skills had flatter trajectories in most language measures. Thus, two distinct language profiles emerged for children with ASD.

Social and linguistic explanations have been proposed for pronoun reversals in young typically developing (TD) children and those with autism spectrum disorders (ASD). The current study breaks new ground in investigating both explanations, comparing 18 TD toddlers and 15 children with ASD at similar language levels. Spontaneous speech was sampled every four months for six visits. Vocabulary and joint attention were also measured. Both groups produced pronoun reversals at low rates. The ASD group produced somewhat more reversals than the TD group, overall and at multiple visits. In the ASD group, early language and joint attention scores contributed significantly and independently to the incidence of reversal. Both linguistic and social factors seem implicated; moreover, reversals seem to occur when children’s language and social abilities develop asynchronously. These findings can help clinicians devise both linguistic and social interventions for the relevant children.

Little is known about whether early symptom presentation differs in toddlers with ASD from ethnic minority versus non-minority backgrounds. Within a treatment study for toddlers with ASD, we compared 19 minority to 65 Caucasian children and their parents on variables obtained from the Mullen Scales of Early Learning, Autism Diagnostic Observation Schedule, and Communication and Symbolic Behavior Scales Caregiver Questionnaire. The majority of parents were from the upper classes irrespective of ethnic membership. Minority children had lower language and communication scores than non-minority children. Findings indicate that subtle communication delays may be undetected or presumed unremarkable by parents of minority toddlers, and that more significant delays are needed to prompt the search for intervention services.