Interlanguage Errors in the Written Work of Korean High School EFL Students

The study explores the common types of grammatical errors in the written interlanguage of intermediate-level first-year high school EFL students. Employing the error classifications of Dulay et al. (1982) and Ferris (2002), the analysis identified verb form errors as the most prevalent (26%), followed by errors in word form (17%), article/determiners (16%), prepositions (15%), and sentence structures (10%). The findings indicate that interlingual transfer is the primary source of errors across all examined categories, while intralingual transfer significantly contributes to errors in tense usage. These results underscore the need for targeted pedagogical interventions focusing on verb forms, word forms, articles, prepositions, and sentence structures to enhance the grammatical accuracy of EFL learns. The study offers practical implications for EFL educators aiming to improve students’ writing proficiency and suggests areas for further research in error analysis and interlanguage development.