- Students with autism spectrum disorders (ASD) frequently demonstrate language delays (American Psychiatric Association 2000). This study investigated the effects of a Direct Instruction (DI) language program implemented with elementary students with ASD. There is little research in the area of DI as a language intervention for students with ASD. This study examined the effectiveness of DI with regard to students' oral language skills, specifically the identification of materials of which objects were made. A single-subject changing criterion design was employed. A functional relation between DI and oral language skills was demonstrated through replication of skill increase over three criterion changes and across three students. The results and their implications are discussed further.