Previous research reported that 5% of elementary students in Korea face developmental dyslexia challenges. However, due to emphasis on oral communication in English education, students struggling with English reading may be mistakenly perceived as lacking motivation or being influenced by environmental factors. Accordingly, this study investigates the English spelling proficiency of a Korean student at risk of developmental dyslexia over two years, spanning from 6th grade in elementary school to 1st grade in middle school. The analysis, based on the student's school-related writing materials and private school assignments, revealed consistent patterns of errors over the two years. In the sixth-grade year, 2,509 words were examined, with 60 (2.39%) misspelled words. In the first-grade middle school year, 15,592 words were assessed, with 313 (2.01%) misspelled words. Persistent errors included vowel deletion, consonant deletion, vowel substitution, vowel insertion, consonant insertion, homonym errors, and letter reversals (e.g., b/d and p/d), albeit with variations in order. These findings highlight a need for targeted interventions in teaching English spelling to Korean students at risk of dyslexia or reading difficulties. The study emphasizes the importance of recognizing error patterns and tailoring instructional approaches to address the challenges faced by these students.