The study investigated the effects of recasts and prompts on learning language forms that arose incidentally in dyadic interaction, focusing on the degree of explicitness of each type of feedback and learner proficiency levels. The data were collected from 64 beginning and upper-intermediate English learners of Korean. Thirty-one beginning learners were randomly assigned to a feedback group and to a control group, and thirtythree upper-intermediate learners were also assigned to a feedback group and to a control group. Each learner was paired with an English speaker and worked on a picture-sequencing task. The learners in the feedback groups received recasts or prompts on their erroneous utterances while the learners in the control groups did not. The effects of feedback were measured by pre-interaction picture descriptions and immediate and delayed post-interaction correction tasks. The study found that both recasts and prompts had some effects on learning the targeted forms, and more explicit forms of each feedback resulted in a higher rate of correction. The beginning learners took more advantages of recasts relative to the upper-intermediate learners, and explicit prompts worked better for the upper-intermediate learners. The effects of prompts sustained longer than recasts in both levels.

The study investigated whether Korean EFL students' vocabulary used in reading-based writing differed according to writing topic and their reading and writing proficiency. College students enrolled in writing courses (n=95) were asked to write argumentative essays in response to two readings on judging people by appearance (JPA) and disclosing personal information of serious criminals (DPI). These students were divided into high and low proficiency writer groups and into high and low proficiency reader groups according to their writing and reading scores respectively. The students' vocabulary used in writing was then analyzed by VocabProfile, which provided four lexical frequency lists: the first 1000 frequent words (K1) including function words (FW) and content words (CW), the second 1000 frequent words (K2), academic word list (AWL), and off the list words (OLW). The results indicated that the topic JPA produced a higher proportion of K1 and content words, whereas DPI generated more K2 and off the list words. None of the vocabulary profiles, however, significantly differed according to the students’ reading proficiency. In contrast, proficient writers were found to use significantly more K1 and function words than their counterparts. With the topic effect further considered, for JPA, proficient writers used more K1 words and function words whereas less proficient writers used more K2 and off the list words. With regard to DPl, proficient writers were found to use more function words than low proficient writers. Findings are discussed in more detail, along with implications.