Multimodal Communication in Autism Is Reorganized, Not Reduced: Evidence From Speech and Gesture Across Four Languages.

Speech and gesture form an integrated communicative system, yet how this system operates in autism, and whether it varies across languages, remains unclear. We examined narrative production in 88 children (44 autistic, 44 neurotypical [NT]), matched on age, socioeconomic status, and nonverbal IQ, acquiring English, French, German, or Spanish, using a structured storytelling task (Autism Diagnostic Observation Schedule, ADOS-2 Monkey Story). Speech and gesture were analyzed along parallel dimensions of amount, diversity, and complexity. Autistic children produced comparable speech amount and lexical diversity to NT peers but differed in complexity. Critically, autistic children produced gestures more frequently, with greater diversity and complexity, including gestures conveying additional semantic information. This pattern indicates that gesture contributes meaningful information alongside speech. Cross-linguistic analyses revealed limited variation in speech but robust language-related differences in gesture across both groups. These findings are consistent with a reorganization of multimodal communication in autism rather than a reduction, highlighting gesture as an integral component of communicative expression across languages.