Decontextualized Language Skills in Children with Developmental Language Disorder and Developmental Dyslexia: Evidence from a Word Definition Task

The present study investigates the development of decontextualized language skills, by means of a word definition task, in children with Developmental Language Disorder (DLD) & Developmental Dyslexia (DD). Although these disorders have a common basis and have studied for different aspects of language abilities, no studies, to date, have compared them in terms of their word definitional skills. Addressing this gap, the present study examined thirty-six children with DLD, or DD or typically developing (TD) age-matched children. All participants were tested on their expressive vocabulary, non-verbal abilities and on their definitional skills. In the definitional task they had to define 16 words (8 nouns, 4 verbs, and 4 adjectives; simple vs. compound, abstract vs. concrete) orally. Definitions were evaluated on both content and form. Results have shown that more decontextualized language was used by the TD group than by the two impaired groups and the DD group exhibited the use of more decontextualized language than the DLD group. By contrast, no differences were found among the groups in form. Delving into different word characteristics more demanding were found to be abstract and compound words. DLD group faced more difficulties than the other groups in compound abstract nouns. Fewer differences were found in verbs suggesting that formal definitions of verbs are equally demanding for all groups. Findings suggest that these two disorders have more similarities in most of the categories in terms of the use of decontextualized language. The present study offers new knowledge on the development of definitional skills and indicates that research should investigate them in the light of interrelation of different word characteristics; otherwise the picture we get can be misleading.