Definitional skills of learners with and without developmental language disorder

Abstract

Definitions exhibit aspects of mental lexicon organization. Learners with Developmental Language Disorder (DLD) have limited vocabulary knowledge (in breadth and depth) and, thus, less mature definitional skills. Word characteristics affect the definitional skills. This study investigated the definitional skills of learners with and without DLD considering different word characteristics. Moreover, issues like deviant vs. delayed abilities and the link between breadth and depth of vocabulary knowledge are addressed. Thirty-six learners were divided into three groups (a DLD and two control groups [CG] of typically developing learners matched on either age or vocabulary). They were asked to define 16 words. Answers were scored for content and form. Findings revealed that the DLD group scored lower than both CGs in content, while no differences were found in form. Definitions of abstract and compound words were more demanding for all. Correlations between vocabulary and definitional skills were detected only in the age-matched CG. From the above, we deduce that DLD learners’ definitional skills are deviant. In addition, clinical practice should not look at effects of isolated variables, but rather investigate the interrelation of different parameters. Finally, the link between breadth and depth of vocabulary knowledge may require more time to emerge in DLD learners.