Speed of Processing in Developmental Language Disorder (DLD): The Case of Real-Time Grammatical Processing

Background: Developmental Language Disorder (DLD) impacts various aspects of children's language abilities, including the processing of inflectional morphology. Prior research suggests that children with DLD exhibit deficits in processing speed and sensitivity to grammatical inflections, yet the relationship between these deficits remains unclear. Aims: This study aimed to investigate the relationship between processing speed and sensitivity to inflectional morphology in children with DLD, focusing on their real-time processing abilities in response to regular past tense, third person singular, and regular plural inflections at different rates of sentence articulation. Method: Eighteen children with DLD and 18 age-matched controls underwent word monitoring tasks that assessed sensitivity to grammaticality of inflections in sentences presented at normal and slow rates of articulation. Results: At a normal rate of articulation, children with DLD demonstrated slower response times and reduced sensitivity to grammaticality across all inflections compared to controls. When the articulation rate was slowed, children with DLD showed improved sensitivity, particularly to regular plural and third person singular inflections, although deficits in processing the regular past tense persisted. Conclusions: The findings suggest a significant relationship between processing speed and inflectional morphology sensitivity in children with DLD. Slower articulation rates improved grammatical sensitivity for certain inflections, highlighting the potential of tailored interventions that consider processing speed limitations. Persistent difficulties with the regular past tense inflection indicate the need for targeted support for children with DLD in this area.