Vocabulary in the Textbooks of Teaching Persian toNon-Persian Speakers: A Corpus-Based Study

Methods and tools of corpus linguistics were used to compute the rate of overlap between the high frequency words of textbooks and those of a Persian language corpus. Based on the texts of Persian Language Data Base, a balanced corpus was developed and its high frequency words were used as benchmarks against which textbooks’ high frequency words were compared. Three textbooks which are widely used in centers for teaching Persian to Non-Persians were selected. The 5000 most frequents words of each book were organized into five 1000 word lists. Each of the 1000 word lists was taken as representing a level of language learning. Each book’s five word lists were compared to their corresponding word lists drawn from the reference corpus. The findings indicated that in regards to language learning levels, the amount of lexical overlap between 1000-word lists of books and those of the reference corpus is very low. Even in the first 1000-word list which due to the presence of large number of function words was expected to yield 100% overlap, the highest degree of overlap (i.e. Rasuli’s book) was nearly 55%. In the other vocabulary learning levels, e.g. level 5, the rate of overlap between the textbooks and the reference corpus was less than 2%. It was concluded that in some of the language learning levels, there was less than 2 percent overlap between the high frequency words of textbooks and those of the reference corpus. When the subject of language learning levels was set aside and merely the rate of overlap between high frequency words of the textbooks and those of the reference corpus was calculated, less than 50% overlap was observed.