The study investigates which grammar features need high priority of pedagogical intervention to develop implicit knowledge, unlike grammatical features in need of explanation of explicit rules. Two types of data were collected from 29 Korean college students: a sentence completion test in English and a meta-linguistic knowledge test (requiring students to both correct the underlined error and explain the grammatical rule) in Korean. Through statistical analyses, including a Wilcoxon signed rank test, this study finds significant differences in test achievements for tense, time prepositions (for and since), subjunctive moods, dative alternations, quantitative adjectives (many and much), gerunds, and third-person singular -s in the simple present tense. Based on results obtained, this study proposes which specific grammar features need intensive pedagogical intervention for production skills, including sentence writing and speaking. Several practical suggestions are provided for EFL instructors and researchers to make more effective use of speaking and writing activities as well as formative testing.

This study was conducted to investigate the effects of the sentence-writing task on English vocabulary learning of Korean high school students. The effectiveness of the sentence-writing task can be explained based on the Involvement Load Hypothesis (Laufer & Hulstijn, 2001); yet, there has been no consistency in the results of the previous studies on this hypothesis. In the present study, the effects of the sentence-writing task on vocabulary learning were re-examined in comparison with the gap-filling task. In addition, considering that there have been no studies addressing the effects of autobiographical elaboration (relating the meaning of a certain word to one’s own experience) on memory, the effects of the autobiographical sentence-writing task were compared to those of the imaginary sentence-writing task. Forty high proficiency and 40 low proficiency learners were randomly assigned either of the sentence-writing or the gap-filling task. The results demonstrated that the sentence-writing task is more effective in vocabulary learning than the gap-filling task, regardless of the learners’ proficiency levels. However, no significant difference was found between the effects of the autobiographical sentence-writing task and the imaginary sentence-writing task. Based on the results, the pedagogical implications were discussed in the conclusion chapter.