A comparative study of language phenotypes in Autism Spectrum Disorder and Specific Language Impairment

Background: Problems with communication and language are among the main characteristics of both Autism Spectrum Disorder (ASD) and Specific Language Impairment (SLI). The main objective of the present study was to analyze whether the two disorders have similar formal language profiles. Method: The study involved three groups of 20 students each, divided into ASD, SLI, and Control, of similar ages and IQ. The CELF-4 standardized test was administered to assess their language skills. Results: No significant differences in language were found between the SLI and ASD groups, with no effect sizes. Differences were observed between the SLI and ASD groups when they were compared separately with the Control group, with a large effect size. Conclusions: There is an overlap in the linguistic profiles of children with SLI and children with ASD. Similarity is thus confirmed in comprehensive and expressive language, as well as in morphosyntactic and lexical-semantic production.