A research was carried out into speech errors in Farsi aiming at categorizing them. As many as 1064 speech errors were simultaneously classified on two lingual and Para lingual axes. The relations of substitution, interchange, addition, omission, and mixture constituted the parts of Para lingual axis. Categories of phonology morphology, and syntax on the other hand were included on the lingual axis. No relationship was proved to exist between the factors of sex and education on the one hand and parts of lingual and Para lingual classification on the other hand. The results of x2 tests confirmed the relationship between sex and the frequency of speech errors in Para lingual relations and lingual categories, as well as the relationship between education and the frequency of speech errors in Para lingual relations.
However, the results of x2 tests did not prove any relationship between education and the frequency of errors in lingual categories.
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