چكيده
Having a clear picture about the quantity of vocabulary input in textbooks is specially important in foreign language learning. Vocabulary is a very important part of any language. Vocabulary frequency is a topic that has raised interest of many researchers and teachers over the last seventy years. In spite of changing local English textbooks in Iran, there are some weaknesses in recently published books and the necessity of evaluation of these textbooks seems undeniable.The purpose of this study was evaluating English junior high school textbooks in Iran withthe focus on analyzing the vocabulary level. These books have been preparedby the Ministry of Education and Culture for use in Iranian Junior high Schools. These textbooks, wereanalyzed and compared using Lexical Frequency Profiler(LFP) software to check the frequency range of words.The output of lexical profiles for each book indicated that the number of off-list words and AWL words was not appropriate in comparison to K1 words and K2 words in Prospect 3. Prospect 1, 2 and 3 did not have the appropriate frequency level for learning English. For learning English as a beginner, understanding of 95% of the words is necessary for comprehension while this expectation has not been met in Prospect 1 and 2. Prospect 3 is relatively close to the desired level. The result of this research indicated that the level of learners is not considered in Prospect text books. K1(71.98, 76.86, 82.63) increased with increasing the level, but it is under 95%. K2
(14.98, 9.29, 9.32), AWL(0.48, 1.02, 0.91) andoff-list(12.56, 12.83, 7.14) decreased as the level of the book increased. Naturally, Awl and off-list words are acceptable for beginners. The type/token ratio(0.53, 0.41, 0.31) and lexical density(0.63, 0.55, 0.51) in textbooks decreased at the level of the books increased.The higher the lexical density,themore complex the text.It is expected that the increase in the levels of the books thehigher type/token ratio and lexical density percentage, K2highertoo but in the book series under this study it was decreased.The results of the present study can be used by student school books publication or any other types of organizations that are responsible for the design and development of the English textbooks
