This study compared the use of lexical bundles in authentic spoken language data with those of two English learning textbooks developed for IELTS preparation courses in Iran. The aim was to see if the language chunks available in the said textbooks were representative of the real-life language for which learners need to prepare. To achieve this aim, firstly, a list of lexical bundles was compiled based on Michigan Corpus of Academic Spoken English (MICASE) and British Academic Spoken English (BASE). Further, the list was used as a reference tool to analyze the language data of two IELTS preparation books published and widely used in Iran. The results highlighted some considerable differences between MICASE and BASE with regard to the use of lexical bundles in terms of their frequency, structure, and function. Moreover, it was revealed that the books under investigation shared only a scarce number of similar lexical bundles with MICASE and BASE as a whole. Therefore, they failed to be representative of the authentic language that people use in real world. Finally, the implications of the study are discussed, and several practical suggestions are made in order to inform teachers, material developers, and syllabus designers of the importance of related corpus linguistic studies.
