The aim of this research was to determine which postpositions should be taught at different levels of proficiency in teaching Turkish as a foreign language and propose an instructional program for their teaching. To that end, the frequency of the postpositions in the course books was analyzed in terms of proficiency levels and the types of teaching activities used for their teaching were examined, and an instructional program for teaching postpositions was proposed. The frequency of the postpositions was examined by using data from the TS Corpus and expert opinions were additionally obtained to ensure consistency and accuracy in teaching them. For data collection, content analysis of the course books by four publishers was conducted and the distributions of the data were calculated considering proficiency levels. This was followed by the examination of the teaching strategies and techniques used in the teaching of postpositions. The frequency of occurrence of the postpositions in the TS Corpus was determined subsequently. The analysis of the corpus data showed that postpositions occurred at the C1 level the most and at the A1 level the least. Course book examinations showed that postpositions used to express the instruments used, cause and those that were used in questions were the most commonly used ones. Postpositions that are used to express predictions and purpose were the least used ones. In the TS Corpus, the most commonly used postpositions were those that express cause. It was determined that 11 techniques were used in the textbooks for the teaching of postpositions. The most common techniques used in the teaching of postpositions were fill-in-the blanks, sentence completion, multiple choice and sentence construction. The least used techniques were matching, open-ended questions, guided writing, making sentences using cue words, word pools to make sentences, choosing the right word and guided speaking based on cue sentences.
teaching Turkish as a foreign language (TTFL), postpositions, course books, corpus.