Korean EFL learners' knowledge of semantic, morphological, and syntactic properties of English verbs: the relationships of lexical and grammatical knowledge
The purpose of this study was to investigate the relationships between lexical and grammatical knowledge in the L2 acquisition of English by Korean EFL learners by examining how the depth of lexical knowledge that Korean learners have about English verbs is related to their grammatical knowledge. For this study, L2 research into depth of lexical knowledge and generative syntactic theory have been reviewed to suggest the interdependent nature of vocabulary and grammar in L2 acquisition (Nation, 1990, 2001; Chomsky, 1981, 1986, 1995; Herschensohn, 2000). Data were collected from Korean EFL learners through a depth of vocabulary knowledge test which focused on semantic, morphological, and syntactic properties of English verbs and a grammar test. The results showed that there was a high positive correlation between vocabulary and grammar knowledge in L2 English acquisition by Korean learners, and that semantic, morphological, and syntactic properties of lexical knowledge all contributed to the prediction of L2 learners' grammatical knowledge. In particular, the syntactic property of lexical knowledge was found to be the most important predictor of grammatical knowledge. However, it was also found that the morphological property was not as important in the prediction of L2 grammatical knowledge as the syntactic property. Based on these findings, it was argued that the in-depth view of L2 lexical knowledge might be appropriate for explaining the interdependent nature of lexical and grammatical knowledge, since this in-depth perspective sees lexical knowledge as consisting of various properties such as semantic, morphological, and syntactic features. On the other hand, a generative view on syntax also seems to provide an account of how each property of lexical knowledge would be related to overall grammatical knowledge. Thus, the syntactic property of word knowledge such as argument structures and subcategorization frames might serve as a connector which links lexical and grammatical knowledge. Finally, some possible accounts of why the morphological property of vocabulary knowledge did not contribute as much to the prediction of L2 grammatical knowledge as the syntactic property were provided on the basis of the notion of argument structures, the characteristics of morphological knowledge assessed by the in-depth vocabulary test, and L2 lexical development model proposed by Jiang (2000).