2020 年 64 巻 p. 79-93
The present study aims to set vocabulary size targets for high-stakes English tests to be used as part of university entrance examinations in Japan from the 2020 academic year. This was done by profiling lexical frequency levels of seven candidate tests: Cambridge First, EIKEN, GTEC, IELTS, TEAP, TOEFL, and TOEIC. Assuming that marginal words, transparent compounds, and abbreviations do not impede test takers’ comprehension, it took the most frequent 2,000 to 3,000 word families from Nation’s British National Corpus and Corpus of Contemporary American English word family lists to account for 95% of running words appearing in listening passages of the samples. With respect to reading passages, the most frequent 2,000 to 5,000 word families were necessary to yield 95% lexical coverage. If 98% coverage is desired, then the most frequent 3,000 to 5,000 and 3,000 to 8,000 word families were required for the listening and the reading texts respectively. The present study also compared vocabulary size targets for reading comprehension passages derived from the current and the previous versions of Cambridge First. Vocabulary demands of the updated and the previous versions of TOEIC were also compared. It is suggested that vocabulary size to achieve 95% coverage in reading passages of the current version of Cambridge First is equal to that for the previous version. Results of the present study also indicate that vocabulary size targets to yield 95% and 98% coverage in the current version of TOEIC are identical to those for the previous version.