Evaluation of an explicit instructional approach to teach grammatical forms to children with low-symptom severity autism spectrum disorder

Purpose: Weaknesses in the use of grammatical forms may reduce the functional use of language for verbally expressive children with autism spectrum disorder (ASD) and exacerbate difficulties with academic and social skill development. This early efficacy study evaluated a combined explicit–implicit instructional approach to teach novel grammatical forms to children with ASD. Method: Seventeen children with ASD between the ages of 4 and 10 years who demonstrated weaknesses in expressive grammatical language completed 2 tasks, each targeting a different novel grammatical form. One form was a gender marking, which required the child to modify the verb if the sentence subject was a boy. The other form was a person marking, which required the child to modify the verb if the sentence subject was the 1st person, “I.” Each form was targeted using implicit-only instruction or combined explicit–implicit instruction. With implicit-only instruction, the examiner presented models and recasts of the targeted form. With explicit–implicit instruction, the examiner presented the rule guiding the form as well as models and recasts. Learning was assessed during each of 4 treatment sessions and after a 1-week delay in 2 contexts. Results: For the gender target form, significantly more children reliably produced the target form with explicit– implicit instruction (χ² = 4.10, p = .04). For the person target form, the difference in instruction was not statistically significant. Task performance revealed a positive association with receptive language skills, but not age, nonverbal intelligence, or severity of autism-related behaviors for the person form. Conclusion: This study provides preliminary evidence that expressively verbal children with low-symptom severity ASD can successfully learn novel grammatical forms with intervention that comprises both explicit and implicit instruction.