Do grammatical variations between languages influence early language acquisition in autistic individuals?

Could grammatical variations between languages influence early language acquisition? This question has been largely overlooked, likely due to the challenges of studying it in typically developing children. By around four years of age, most typically developing children naturally acquire advanced syntactic abilities. In contrast, autistic children often face significant difficulties with language acquisition, with approximately 40 % of those diagnosed with autism never achieving full syntactic language comprehension. If grammatical differences between languages impact syntactic acquisition, autistic individuals speaking different languages could potentially display distinct syntactic development trajectories. To explore this, a longitudinal study was conducted involving children aged 2–5 years diagnosed with Autism Spectrum Disorder (ASD) who utilized a language therapy app that also gathered parent-reported language assessments. Participants were divided into groups based on their native languages: English (N = 5557), Spanish (N = 1763), Portuguese (N = 830), Italian (N = 417), and Russian (N = 313). A linear mixed-effects model with repeated measures was employed to compare each pair of language groups. The analysis revealed no significant differences in the 3-year trajectories of receptive and expressive language development between the groups. These findings suggest that all studied languages are equally effective in supporting language development.