Difference in Language Profiles of Children With Autism Spectrum Disorder and Down Syndrome Is Not Driven by Non‐Verbal Cognition

What is already known on this subject Language profiles of children with Autism Spectrum Disorder (ASD) and Down syndrome (DS) have been described in previous studies on different languages. Usually, non-verbal IQ has been reported as one of the main predictors of language functioning in these groups of individuals with neurodevelopmental disorders. However, there is a lack of direct comparisons of language profiles at different linguistic levels in these groups, matched by non-verbal IQ and using standardized language assessment tools to understand whether the nature of language impairments is common or different in ASD and DS regardless of non-verbal cognition. What this study adds to the existing knowledge This study provided a direct comparison of language profiles at different linguistic levels in children with ASD and DS matched by non-verbal IQ. This identified similarities and differences in language functioning at different linguistic levels in children with ASD and DS as well as revealed non-language factors that were associated with language abilities. What are the potential or actual clinical implications of this work? The study showed the differences in language profiles of children with ASD and DS regardless of non-verbal IQ and identified specific impairments related to linguistic levels and structural language characteristics. This knowledge contributes to speech and language therapy strategies, as it elucidates specific 'linguistic deficits' that should be targeted during intervention and therapy.