Spontaneous productions of infinitive clauses by English-speaking children with and without specific language impairment.

As a group, children with specific language impairment (SLI) have presented with lower levels of proficiency with infinitive clauses relative to comparison groups with typical language (TL). The presence of considerable individual variability within those affected by SLI, however, remains unexplained. Furthermore, the status of infinitive clause productions in children with language impairments that do not meet criteria for SLI, because of either low nonverbal abilities or other concomitant conditions, is unknown. Previous studies focused on children with SLI and have not included children who would fit into a broader developmental language disorder (DLD) designation. In this study, spontaneous language samples were collected on 30 children with DLD and 30 children with typical language skills, including those with low nonverbal abilities or other neurodevelopmental disorders (age range: 5;1-7;7). Samples were analyzed to examine potential predictors of children's infinitive clause use and their infinitive TO omission rates. Significant group differences were found for the number and accuracy of infinitive clauses produced. Consistent with previous reports examining children with SLI, considerable variability was found across cases of DLD. Maternal education and mean length of utterance (MLU) were significant predictors for children's infinitive clause use. Finite verb morphology composite scores and MLU were significant predictors of children's infinitive TO omission rates.