The Text Analysis of Persian Textbooks for Intellectually- Disabled Students Based on Halliday and Hasan's Cohesion Model

The aim of this study is to investigate the occurrence of lexical cohesion devices in Farsi Textbooks for intellectually- disabled students.
The method is based on the model proposed by Halliday and Hasan. The data is taken from Persian Textbooks for intellectually- disabled students. The elementary school for intellectually- disabled students consists of six grades and for each grade¡ one Persian textbook is designed. SPSS software is used for analysing data and to answer the study questions¡ covariance test is used.
There are some changes in lexical cohesive devices with the increasing level grade. These changes have had significant differences.
A change that occurred with increasing level grade of mentally-disabled students is not significant for the same item¡ superordinate and collocation but it is significant for the frequency of synonymy and general words. In other words¡ frequency of synonymy and general words increases with increasing level grade but the frequency of same item¡ superordinate and collocation has no meaningful changes.