L2英語メンタルレキシコンの構造 ―語彙サイズの異なる日本人EFL 学習者における名詞、形容詞、動詞の単語間結びつき度の比較―

抄録

The purpose of this study was to establish whether Japanese college students having different vocabulary sizes would group a set of English words into clusters differently, representing the ways lexical items are organized in their L2 mental lexicons (ML). Two participant groups, 26 college students with a large vocabulary size (LARGE) whose mean vocabulary size was 6,761.5 and 26 college students with a small vocabulary size (SMALL) whose mean vocabulary size was 5,042.3, by means of the Vocabulary Size Test (Nation & Beglar, 2007), carried out three sorting tasks of 24 words (four semantically connected word clusters of six words) chosen respectively from nouns, adjectives, and verbs. Permutation tests showed that lexical items in all the word classes were represented in a significantly different way between the two groups, while the difference in nouns was almost significant (p = 0.0508) after correcting for the number of iterations of the test. The difference between the LARGE and SMALL groups was largest in verbs, then in adjectives, and smallest in nouns. Identification of the cluster numbers in the group dendrograms revealed that the LARGE group established four or five organized lexical clusters in all the word classes, but the SMALL group established none in the adjective and verb classes. Pedagogical implications for teaching vocabulary are proposed.