総説・解説等

This study addresses the question as to whether the English mental lexicon Japanese college EFL learners have built can develop into a more elaborated structure within a 15-week period of general English education. A free sorting task on a set of 50 high-frequency English verbs was given to 30 first-year college students (NNS) of intermediate low English proficiency in the 2nd ("PRE") and 14th ("POST") weeks. The task was also given to 30 native speakers of English (NS). A pair-wise comparison of the distance matrices of the sorting task results by means of permutation tests showed that the dendrograms of PRE and POST were not statistically significantly different from each other at the 5% significance level (p=0.8509), disclosing that the English mental lexicon NNS have shaped does not easily develop into a more intricately organized structure. The analysis also revealed that both the dendrograms of PRE and NS and those of POST and NS were statistically significantly different from each other at the 5% significance level (p=0.0003). This indicates that the organization of the English mental lexicon of Japanese EFL learners is distinctively different from that of their NS counterparts.That is, the NNS English mental lexicon cannot readily be approximated into the NS English mental lexicon. Furthermore, the examination of the degrees of similarity between lexical items confirmed that the NNS English mental lexicon contains a statistically significantly larger number of hazy, vague lexical links than the NS mental lexicon does.