The impact of individual factors on linguistic alignment of autistic boys and their mothers

Linguistic alignment reflects shared linguistic behaviors (e.g. syntax and lexicon) between interlocutors. Recent work has examined whether autistic children align to the same degree as their non-autistic peers, with current findings inconclusive. This study took an in-depth approach to investigating factors contributing to variation in linguistic alignment among autistic individuals. Eighteen school-age and adolescent autistic male participants, 14 males with fragile X syndrome + autism, and their mothers participated in the study. Dyads engaged in an unstructured conversation for ~12 min. Using Bayesian linear mixed-effect models, we assessed the relationships between alignment and within-individual factors of the participants. Lexical and syntactic alignment were uniquely influenced by within-participant factors. Maternal lexical and syntactic alignment were differentially associated with participant cognitive and expressive language abilities, and according to etiology (fragile X syndrome + autism vs idiopathic autism). This study highlights the complexity of alignment in autistic individuals and their mothers. Results suggest that alignment is a dynamic process that is motivated in part by within-individual traits of their children. Consequently, characterizing alignment in autism requires a highly nuanced and thoughtful approach that accounts for the heterogeneity of the population.

Lay abstract

Shared Language Use in Conversations Between Mothers and Their Autistic Sons

During conversations, we tend to use the same kinds of words as our partners, which is an important skill that helps language development. Researchers have explored this phenomenon among autistic individuals and have not found consistent differences from non-autistic individuals. The current study examined how mothers and their autistic sons communicate with each other during conversations to see the extent to which they used similar words and grammar.

We included 32 school-age and adolescent male participants (18 autism, 14 fragile X + autism) and their mothers. Participants and their mothers talked together how they normally would for 12 min. We transcribed everything they said and evaluated how much they used the same words and grammar as each other. We also looked at how other characteristics, like IQ and language skills, influenced how much they were similar in their language.

We found that mothers and their sons used the same kinds of words at a rate greater than chance. Mothers used similar language as their sons more often when their son had greater language skills. Mothers who had children with fragile X + autism were more likely to use similar words as their son.

This study showed that using the same words and grammar is a very dynamic process that depends in part on language and cognition between two speakers. It is important that future research in this area takes a detailed and thoughtful approach to analysis.