Despite the widespread recognition of the prominent contribution of key language subskills, such as grammar and vocabulary knowledge, to reading comprehension, a research consensus on their relative significance has not been reached. Moreover, the extent of the contribution vocabulary depth makes to reading comprehension has received little research attention. The present study assessed the relative potential contribution of vocabulary depth and grammar knowledge to advanced Korean EFL college students’ reading comprehension abilities, while controlling for their language proficiency and vocabulary breadth, through hierarchical regression analyses. 56 advanced EFL Korean college students were tested on reading comprehension abilities and a range of reading-related subskills including vocabulary breadth, vocabulary depth, grammar, and listening comprehension in English. The findings revealed the unique contribution of vocabulary depth to reading comprehension abilities beyond the effects of both vocabulary breadth and grammar knowledge when English proficiency was controlled for. The findings further underscore the need for balanced approaches in developing L2 learners’ language skills to enhance their reading comprehension abilities.

I. Introduction
II. Literature Review
    1. Vocabulary Knowledge and Reading Comprehension
    2. Grammar Knowledge and Reading Comprehension
    3. Vocabulary vs. Grammar in Explaining Reading Comprehension
III. Method
    1. Participants
    2. Measures
    3. Analyses
IV. Results
V. Discussion and Conclusion
References

• Yun Cheong Hur(Korea University)
• Yusun Kang(Korea University) Corresponding author