A Study on Autistic Children’s Linguistic Behavior based on Functional Grammar

This study aimed to examine the speech of autistic children aged 6 to 10 in the city of Tehran, Iran based on the three metafunctions of Halliday's Systemic Functional Grammar (SFG) theory and to strengthen the connection between psychology and linguistics. The research method in this study was a combination of quantitative and qualitative approaches. Qualitatively, this study was a descriptive-analytical investigation. The statistical population of the study included all children aged 6 to 10 with autism in Tehran in 2018, from which 7 children were randomly selected using stratified sampling. Additionally, a control group of 7 non-autistic children aged 6 to 10 was randomly chosen. Since autistic individuals are generally less verbal, the researcher, with the help of a teacher, recorded and transcribed the speech of autistic children discussing specific visual topics using a mobile phone. The sentences were analyzed based on experiential, interpersonal, and textual metafunctions. Quantitatively, the differences between the two groups in terms of the use of processes, modal verbs, and negative polarity were examined using a two-tailed t-test. Descriptive results showed that the material process accounted for the highest percentage of all processes in the speech of autistic individuals, whereas the existential process accounted for approximately zero percent. This indicates that autistic individuals have difficulty understanding the concept of the existential process. Material processes focus on the occurrence of events, as they are based on our experience of the physical world. In the comparison between the two groups, material processes had the highest mean in both groups, followed by relational and mental processes.