Abstract
The purpose of this study is to analyze Nation's Vocabulary Levels Test (VLT) to check its validity, to develop a vocabulary size test for Japanese EFL learners and to give a portion of it to a sample of learners to compute the reliability of the newly developed test. According to the four surveys of VLT, four problems were pointed out; too high a ratio of loan-words in Japanese, difficulty in understanding the definitions of words, inadequacy of employing word family counting, and the use of classical vocabulary lists. Based upon these findings, a Japanese version of vocabulary size test was developed and given to 817 students at junior high school, senior high school and university levels. The results of this test showed that forms [1], [2] and [3] have a relatively high reliability coefficient, while forms [4] and [5] have some room to be improved. Further improvement of this test is suggested for future research.
