Investigating linguistic errors of a third grade Persian language student with Down syndrome based on Cognitive Linguistics: Case Study

This research investigates, describes and analyzes the linguistic errors of a Persian speaking student with Down syndrome who studies in the third grade of elementary school. The aim of the research is to apply the concepts of Cognitive Linguistics in the analysis of the samples of this student's narrative speech. For this purpose, research data were collected by Nili-pour et al.'s language test (2023) and Speech Therapist assessment by recording the subject's speech. After collecting data, the researcher classified the errors in the form of tables. Investigations and analyzes showed that this person has more problems in micro-syntactic structure than macro-syntactic structure. In fact, this student has acquired what Tomasello (2003) has named to as core schema and syntactic construction. So, the schemas proposed by Lakoff (1987) have not been formed in this student. Also, this student does not use abstract words in his speech, and he don’t use the correct forms verbs and timed relations was also imperfect. It is suggested that in speech therapy training for this student, along with the current teaching methods, methods based on strengthening the schemas proposed by Lakoff should be designed and carried out to improve the macro-syntactic structure.