Receptive Vocabulary, Phonological Short-Term Memory, Theory of Mind and Oral Inferential Comprehension in French-Speaking Preschoolers With and Without Developmental Language Disorder.

Background And Aims: Inferential comprehension difficulties and their impacts on reading comprehension are well documented in school-aged children with Developmental Language Disorder (DLD). In comparison, fewer studies have been conducted in young children with DLD prior to their formal schooling journey. In addition, the contribution of linguistic and cognitive skills to oral inferential comprehension abilities in preschoolers, notably receptive vocabulary, phonological short-term memory, and theory of mind (ToM), requires further investigation. The first aim of this study is to explore how young children presenting with DLD aged 5 to 6 years perform when compared to same-age and younger children presenting with typical language development (TLD) on measures of oral inferential comprehension, receptive vocabulary, ToM, and phonological short-term memory. The second aim is to analyze how these linguistic and cognitive skills contribute to oral inferential comprehension in both DLD and TLD preschool children.

Methods: A total of 112 preschool children participated in this study, including 21 ( = 21) children with DLD aged 5 to 6 years and two TLD groups, 37 ( = 37) younger children aged 4 to 5 years and 54 ( = 54) same-age children. A narrative-based oral inferential comprehension task was administered to all children, in addition to measures of receptive vocabulary, phonological short-term memory, and ToM. Analysis of covariance (ANCOVAs) were used to compare performances between the three groups, followed by Pearson correlations and hierarchical regression analyses to examine the contribution of these variables to oral inferential comprehension abilities across the sample.

Results: After controlling for level of parental education (LPE) and biological sex, children with DLD performed significantly below the same-age TLD group on all four measures with large effect sizes ( < .001;  = .17-.44). Their performance was comparable to the younger TLD group on measure of oral inferential comprehension ( = .234), and significantly below on measures of receptive vocabulary ( = .008), phonological short-term memory ( < .001), and ToM ( = .028). Results from the regression analysis indicated that age, LPE, diagnosis condition, receptive vocabulary and ToM accounted for 53% of the total variance in oral inferential comprehension.

Conclusions And Implications: This study reiterates the early listening comprehension difficulties experienced by preschool children with DLD when compared to children presenting with typical language development. The results also indicate that when controlling for age, LPE and diagnosis condition, children are likely to have better inferential comprehension abilities if they perform well on a measure of ToM. Considering that challenges related to language comprehension are acknowledged to be persistent and less responsive to intervention, these findings can help inform the development of evidence-based interventions aiming at supporting language comprehension of young children with DLD.