A Quantitative Analysis of Vocabulary Taught in Japanese EFL Textbooks
Abstract This research evaluates vocabulary taught in government-approved Japanese EFL textbooks intended for senior high school students in two different ways: by calculating the proportion of high-frequency words in textbooks and by calculating how many types of core high-frequency words are taught in textbooks. To this end, vocabulary words in textbooks are compared to those in the New General Service List (NGSL), which consists of the top 2,801 high-frequency words in general English. Results show that textbooks are largely made up of words in the NGSL at a statistically significant level with larger than 92% lexical coverage; however, textbooks do not sufficiently cover words in the NGSL at a statistically significant level with up to 38%. Overall, research findings indicate that vocabulary words textbooks provide may be what learners frequently come across in the real world, but those words cannot suffice in order for learners to read English texts intended for native speakers. Therefore, language teachers need to give learners additional input of core words through homework or classroom activities to widen their vocabulary size.