فاطمه نعمتی

Autism Spectrum Disorders refers to a spectrum of disorders that impair autistic children’s various comprehension and production abilities from social to language abilities. Autistic children’s language impairments have discouraged their parents and practitioners from teaching them a second language or growing them up in a bilingual context. However, the previous studies have found that second language learning and bilingualism not only do not disturb autistic children’s language development but also improve their metalinguistic awareness and cognitive abilities. More research is required to gain a deeper understanding of second language learning impact on autistic children’s language and cognitive abilities, especially the widely neglected issue of their lexical processing. This thesis aimed to explore the influence of second language learning on autistic children’s naming latency, naming accuracy, and lexical competition as the components of lexical processing. To this aim, 6 Iranian autistic EFL learners (7 to 17 years old) were recruited from a psychiatric hospital in Shiraz. They were almost homogenous with close verbal and non-verbal IQ scores which were measured through Mac Arthur- Bates Communicative Development Inventory and Good-enough draw-a-man tests. Their naming latency and naming accuracy were measured through picture naming tasks in two times, before and after the instructional treatment. They were taught English lexical items through video modeling using a combination of Discrete Trial Training and Fluency Training methods. The pictures of pretest were all named in Persian and the pictures of posttest were named in both Persian and English. The collected data were analyzed using linear mixed-effects regressions and generalized linear mixed-effects regressions. The results demonstrate that learning English lexical items did not harm their naming accuracy and naming latency; although, verbal IQ score and concreteness influenced their naming accuracy a