This study investigated the effects of exposure frequency, depth of processing, and activity repetition types on vocabulary learning. In total, 78 South Korean fifth-grade students were divided into four conditions. Students in each condition were asked to read a passage with four of the eight target words (exposure: four times) and the other four words (exposure: once) for three days, and to perform the vocabulary activities assigned to each condition. According to the results, exposure frequency and activity repetition type had significant effects on vocabulary learning. Activity repetition type also had a significant interaction effect with exposure frequency and depth of processing. Notably, presenting a word 12 times (4x3) in reading intervals had a more positive impact on vocabulary learning than presenting it three times (1x3), particularly when different vocabulary activities were repeated. Meanwhile, when the same activity was repeated, an activity with a higher depth of processing was more effective for vocabulary learning.

This study investigated the relative predictive power of vocabulary depth and reading fluency on the reading comprehension of advanced Korean EFL learners in college. By doing so, the scope of paradigmatic relations, as part of vocabulary depth, was extended to encompass associative vocabulary as well as synonyms and antonyms, and reading fluency at the discourse level was considered. For this study, 139 college students were tested on a range of vocabulary depth tests, as well as reading comprehension and text-level reading fluency. The findings revealed that although both vocabulary depth and reading fluency are significant contributors to reading comprehension abilities, the predictability of vocabulary depth was larger than that of reading fluency. In addition, associative vocabulary not only revealed additional predictive power for reading comprehension on top of reading fluency, synonyms and antonyms, but also showed stronger predictability compared to synonyms and antonyms. These results highlight that both vocabulary depth, especially the knowledge of how words are related together, and text-level reading fluency play a crucial role in boosting the reading comprehension abilities of even advanced L2 readers.

This study examined whether vocabulary knowledge has meaningful effects on reading comprehension of Korean high school EFL learners and investigated which specific type of vocabulary knowledge, between vocabulary breadth and depth, plays a bigger role in reading comprehension when the learners’ English language proficiency is taken into account. The participants of this study were ninety eight high school EFL learners in Seoul, Korea, and they were tested on a series of measures tapping on their reading comprehension abilities and vocabulary knowledge in two different dimensions (vocabulary breadth and depth). Their listening comprehension abilities were also measured in order to control for the effects of general oral language comprehension abilities known to be the foremost contributor to reading comprehension and thus to enable focused analysis of the role of vocabulary knowledge. The study findings revealed that 1) vocabulary knowledge itself played a critical role in predicting reading comprehension abilities even after controlling for their listening comprehension abilities and that 2) compared to vocabulary breadth, vocabulary depth played a relatively more important role in predicting reading comprehension, regardless of the learners’ language proficiency. The findings provide important implications for vocabulary and reading comprehension instructions for Korean EFL students.