SUMMARY
In foreign language education, the importance of corpus-based studies has been increasing. The priorities of the words taught in language education are determined within the framework of international criteria set through corpus-based studies. Corpus and sub-corpus consisting of many layers, written and oral, increase the efficiency of the process for both teachers and learners. In teaching Turkish as a foreign language, the focus is usually on the vocabulary content of course materials. Texts in textbooks are the roof for the curriculum and practitioners. In this study, the vocabulary content of A1-level textbooks used in teaching Turkish as a foreign language was examined based on corpus; the most frequently used 1000 words were identified. These frequency lists were compared to 50 million-words produced by Aksan (2017) based on the corpus and the level of similarity was determined. The vocabulary content of textbooks was examined based on the corpus and then sorted by word forms, the rate of the number of total words and different words (type/token) was determined, and each publication examined in the data set was examined comparatively. In terms of the most frequently used words, the similarity level of the findings of Aksan (2017) conducted based on the corpus, the level of similarity of the vocabulary content of the examined book sets was found not to be an ideal level. Although the vocabulary content in textbooks was not sufficient in terms of the words in noun form, it was found that the diversity of adjectives and verbs (lemma) should be improved.