Understanding Word Difficulty in Korean EFL Learners: The Interplay of Frequency, Word Length, and CSAT Inclusion Status

This study aimed to explore the factors influencing word difficulty among Korean EFL learners, focusing specifically on word frequency, word length, and CSAT inclusion status. By examining both the simple and interaction effects of these variables, the study assessed their impact on word difficulty as measured by learners' VST performance. The results indicated that CSAT inclusion status was the most significant predictor; words included in previous CSAT exams (2009-2023) were found to be more challenging than those that were not. Furthermore, word length significantly influenced word difficulty, with longer words presenting greater challenges due to increased cognitive demands. While word frequency was also a significant predictor, its impact was less pronounced than that of the other factors, suggesting that frequency-based assessments may not fully capture the nuances of word difficulty for Korean learners in an EFL context. The study additionally highlighted the complexity of word difficulty through significant two-way and three-way interactions among frequency, word length, and CSAT inclusion status. These interactions suggest that the three predictors dynamically influence each other, rather than functioning independently, to affect word difficulty.