Evaluation of an Explicit Approach

This study is a randomized clinical trial that uses a Sequential Multiple Assignment Randomized Trial (SMART) study design. The study will directly compare the efficacy of an innovative intervention that combines explicit and implicit approaches to a traditional implicit treatment approach to teach true grammatical forms to children with developmental language disorder (DLD). The study will also compare interventions that include sequences of Explicit-added and Implicit-only treatments. Participants will include 5- through 9-year-old children with DLD who present with significant grammatical weaknesses. In Phase 1, 155 participants will be randomized 1:1 to an Explicit-added treatment group or an Implicit-only treatment group. Each participant will complete 32 sessions targeting four unique grammatical forms (8 sessions/form). In Phase 2, "Masters" will be re-randomized to receive no treatment 32 sessions of the same treatment, or 32 sessions of the alternative treatment. "Non-Masters" will be re-randomized to receive 32 additional sessions of the same treatment or 32 sessions of the alternative treatment. Performance will be measured on acquisition, maintenance, and generalization probes obtained immediately,1-, 6-, and 12- months post-intervention. The SMART study design will be used to determine if child factors, including expressive and receptive language abilities, nonverbal IQ, and executive function skills can reliably predict the treatment sequence that optimizes language learning. Study results will help to determine the best sequence approach to ameliorate grammatical weaknesses, one of the core deficits of young children with language impairment.