2009 年 20 巻 p. 131-140
The purposes of this study are (1) to longitudinally measure the receptive vocabulary sizes of Japanese senior high school students (SHSs) for about three years and to show their descriptive statistics; (2) to investigate what percentage of the students made (a) progress, (b) little progress, and (c) negative progress in vocabulary learning during specific year(s); and (3) to describe the longitudinal developmental patterns of the vocabulary size of each student during approximately three years of high school. Two hundred and fifty-two Japanese SHS students took Mochizuki's (1998) VSTs four times during their three-year SHS careers. Various basic indices of descriptive statistics were calculated; then, longitudinal comparisons were conducted, using the data of the identical subjects. The author examined the progresses of each student in each year, person by person. The descriptive statistics and the line graphs of longitudinally-measured vocabulary sizes were shown. It was found that, in a regular course even at "shingakukou," 63.9% of the students made little or negative progress while they were in their second year and 42.2% of the students made little or negative progress while they were in their third year. As many as 14 longitudinal developmental patterns of vocabulary size were found and described in detail.