Derlem destekli bir İngilizce ders kitabı ile geleneksel olarak hazırlanmış bir ders kitabının kelime dağarcığı profillerinin incelenmesi

This study investigates the vocabulary profile of a corpus-informed ELT textbook and a traditionally-prepared ELT textbook in terms of their coverage of 2000 high-frequency words of New General Service List (NGSL). It also aims to demonstrate the similarities and differences in the lexical frequency profiles of each book, using a corpus-based approach. The sample course books analyzed are Touchstone 3 and Headway Pre-intermediate. Vocabulary Profiler Compleat and Frequency tools are utilized to profile the lexical content of the textbooks. The overall profile reveals that vocabulary coverage of the most frequent 2000 words of English (NGSL-1 and NGSL-2) is 74.2% in the corpus-informed textbook and 82.2% in the conventional course book, indicating that they are below the desired level for good comprehension and the lexical coverage of high frequency words in corpus-informed textbook is lower. Moreover, this study examines the type-token ratios (TTR) of the textbooks to find out the recycling rate of the vocabulary. The result shows that both course books, especially the corpus-informed textbook, need more systematic coverage and recycling of high frequency words.