A corpus study of English vocabulary in teachers constructed textbook by English teacher forum of Junior High School in Tuban

Over the last decade, there has been an increase in corpus-based studies and English Language Teaching (ELT) research. Moreover, there are some researches about corpus study, but it has not specifically discussed the textbooks. This study employs corpus-based analysis to focus on the frequency of English vocabulary used by the English Teachers forum to construct English textbooks in Indonesia, especially in the EFL context. Five textbooks for Junior High School in Tuban have been analyzed using AntWordProfiler 1.4.0 free software from Anthony Laurence. The corpus analysis of selected core textbooks contains 82,918 tokens and 6,669 types. Then, the most frequent words used were those included in the category of High Frequently Word, namely nouns, verbs, and determiners. It should be prioritized in the target words to facilitate students’ vocabulary development in the Indonesian EFL context, particularly those in the Tuban district. Besides, the textbooks contained 282-word families of academic words and accounted for about 2.51% of the tokens. In the end, the current research provides teachers with an understanding of which vocabulary they need to teach students to meet the curriculum expectations, and then the English language teaching will be more effective.