Analysing Differences in Mean Length of Utterance between Typically Developing Children and Children with Autism Spectrum Disorder

Abstract

Mean Length of Utterance (MLU) has been used as an effective tool for evaluating the syntactic and morphosyntactic deficits of children with expressive language disorders. Expressive language difficulty in children with Autism Spectrum Disorder (ASD) is a very common phenomenon. However, limited published data are available on the MLU of Bangla-speaking Typically Developing (TD) children and children with ASD. The present study aimed to discern the expressive language skills of ASD children by investigating the MLU. The current study includes 30 Bangla-speaking children diagnosed with ASD aged 6 to 9 years, and 30 Bangla-speaking TD participants aged 4 to 6 years. To explore the relationship between chronological age and MLU, each group was split into two age-based subgroups. Narrative data were collected from the participants using the Picture-Narrative Task. The Mean Length of Utterance in words (MLUw), Mean Length of Utterance in morphemes (MLUm), and the use of Lexical Morphemes (LM) and Grammatical Morphemes (GM) were analysed from the first 50 intelligible utterances. The findings indicated a significant distinction in MLU between TD and ASD participants, as TD participants had higher mean scores than ASD participants. The between-group comparisons suggested that the MLUw and MLUm increased as the children got older in both TD and ASD, and the MLUw and MLUm had a positive correlation in both groups. By providing Bangla-language evidence, this study will contribute to the field of Speech and Language Pathology (SLP) in Bangladesh and help clinicians assess expressive language difficulties in Bangla-speaking children with ASD.

Social Science Review [The Dhaka University Studies, Part-D], Vol.43, No.1, June 2026, pp. 269-288.