Lexicogramatical and Linguistic Complexity of Readings Parts in English Books for Senior High School in Iran

The main objective of this research is investigating the lexicogramatical changes in high school English Textbooks or Teaching Materials. The present paper is based on a Quantitative approach applied for textbooks analysis in order to make a three phases computations: Halliday's lexical density 1985, Ure's Lexical Density 1971 and Flesch reading ease Score respectively. Then the Correlation Co efficiency for both of the lexical density methods with reading ease scale will be measured in order to find the most reliable lexical density method between these two. For the first analyses phase theoretical bases of Halliday's functionalist grammar and transitivity system applied and in the second part because of its statistical and computational nature of Halliday's & Ure's lexical density formulas in addition to some linguistic software such as Flesch readability score software, AntConc and Word used then the results given to SPSS for statistical purposes. At the end, the results show that the most used process in our target books is the Material process, Halliday's Lexical Density method with - 0/999 have the highest level of correlation with Flesch reading ease Score so it can be counted more reliable than Ure's method. Initially it was expected that the readability score falls with the grade promotion, in the other word the higher grades text should have lower readability but unfortunately this prediction was not a reality and the presaid level was in imbalance between grades that is a proof to say that during the textbooks preparation these factors wasn't considered.

کلیدواژه ها:

Functionalist ، Teaching Materials ، Lexical Density