Assuming that implicit and explicit knowledge are two different constructs, the current study takes unpaired English unaccusatives as its target grammar feature to investigate these two types of knowledge among Korean EFL learners. In line with the growing body of research utilizing a battery of tests, this study adopts a combination of validated tests to assess implicit and explicit knowledge. In doing so, this study lends support to previous studies, in that the L2 learners’ two types of knowledge are not on par. The findings indicate that proficiency was not correlated with the learners’ explicit knowledge, while it was highly correlated with their implicit knowledge. Moreover, regardless of the grammaticality of the unaccsuative sentences, the role of subject animacy varied depending on the learners’ different type of knowledge in relation to proficiency. Finally, a critical discussion on the importance of separating the two constructs of knowledge and implications for future research are provided.

This present study concerned whether prompts and recasts that occur during interaction could play a role in L2 development. Adopting an untimed grammatical judgment test and an elicited oral imitation test to measure explicit and implicit knowledge, this study examined the relative effects of prompts and recasts on L2 development of past tense forms. The participants were pre-intermediate learners enrolled in English as a foreign language (EFL) classes at a university in Korea. The learners were assigned to two prompt groups, a recast group, and a control group. The analysis of the untimed grammaticality judgment test revealed that the participants promoted their explicit knowledge of the past tense forms of regular and irregular verbs when prompts were provided. The analysis also showed that the learners who received recasts improved their test scores but only in irregular past tense forms. No significant group difference was found among the treatment groups and the control group in the results of the elicited oral imitation test used to measure implicit knowledge of the target forms. These results indicated that prompts were beneficial for short-term L2 grammatical learning of EFL learners of pre-intermediate level. The implications and limitations are discussed in terms of the role of prompts in driving L2 development.