Élaboration d'un entraînement en morphologie dérivationnelle : quelle efficacité sur les compétences lexicales d'adultes avec Trouble Développemental du Langage (TDL) ?

Introduction. The vocabulary of adults with DLD is often impaired. Studies showed that this difficulty primarily concerns the encoding of new words in this population. Interventions targeting vocabulary through a semantic approach were beneficial for the lexical skills of adults with DLD. However, this approach does not allow for generalization to untrained words, in contrast to the use of derivational morphology.Method. 31 adults with DLD aged 18 to 49 years, participated in the study. Using a three-phase (baseline phase, intervention phase, and no-intervention phase) within-subject design with four testing sessions, we evaluated the impact of a derivational morphology training on the lexical skills of adults with DLD.Results. Results suggest an overall improvement in definition task scores following the intervention phase. Participants showed no significant progress during non-intervention phases, but significant gains were observed after the derivational morphology training. Notably, improvements were found on both List A (trained affixes and trained words) and List B (trained affixes with untrained words), indicating evidence of generalization and a maintenance of the intervention’s effects over time. Discussion. This training had a significant impact on vocabulary, confirming the relevance of targeting derivational morphology interventions to promote lexical outcomes in adults with DLD.