The purpose of this study was to investigate the organization of Taiwanese EFL learners’ mental lexicon, and their English word knowledge in reference to semantic features of L1 Lexicon. Participants were one hundred and five students from a university and an institute of technology in northern Taiwan, and 35 native speakers of English. By means of a TOEFL reading test, and a controlled word association test, the students were assigned to three groups at high-, intermediate- and low proficiency levels. A booklet containing a free word association test, a blank filling test, and a semantic similarity rating test was given to the students and the native speakers to collect the data which were then analyzed by SPSS 13.
The results indicated that Taiwanese EFL learners’ responses in word association tests shifted from syntagmatic to paradigmatic types. In addition, compared with the verb and the adjectival classes, the noun stimuli appeared to elicit more paradigmatic responses. On the whole, the more prominent response type in EFL learners was syntagmatic in contrast to the preference for paradigmatic responses of native speakers. Moreover, EFL learners’ use of the target words, words that express catching sight of something, was guided by the semantic features of L1 lexicon as indicated by the invariant pattern of semantic space across proficiency levels. Furthermore, translation seemed to be a common strategy for L2 word learning, and the learning of the target words appeared to be positively related to the frequency load of the senses.
Hence, on the basis of aforementioned findings, the study concluded that a) the mental lexicon of native speakers and that of EFL learners in this study were organized differently, b) nouns seemed to occupy a pivotal status across languages, c) Taiwanese EFL learners’ word knowledge was guided by the semantic features specific to their mother tongue, and d) the frequency load of word meanings appeared to have an impact on the acquisition of word knowledge.
The study, therefore, suggested that semantic elaboration activities will be conducive to the learning of the synonyms or near-synonyms as they will enhance the depth of word knowledge and at the same time enlarge the vocabulary size of learners. In addition, since learners might use translation as a strategy to shortcut the learning process, it would be legitimate to include translation into the curriculum. Finally, to probe the development of vocabulary learning and the structure of mental lexicon in EFL learners, it is recommended that future studies include participants of different language and educational backgrounds, and use word association tests for fixed intervals of time.