Language proficiency is essential for learners’ academic and professional success, particularly in English, the primary medium of instruction in the Philippines. However, many Senior High School learners struggle to apply vocabulary effectively in writing, especially in technical-vocational tracks. Despite existing literacy studies, limited localized research examines how lexical proficiency influences writing performance in these contexts. This study addressed this gap by assessing the lexical proficiency of Grade 12 learners specializing in Electronic Products Assembly and Servicing (EPAS) and its relationship with their functional composition writing in English for Academic and Professional Purposes (EAPP). Using a descriptive–analytical design, data from 40 respondents were gathered through a validated researcher-made instrument and analyzed using descriptive and inferential statistics. Findings revealed that learners had adequate basic vocabulary skills but limited higher-order lexical processing. While they could use words functionally, they struggled with contextual understanding and applying vocabulary in writing. Their writing showed partial competence, with organized ideas but weaknesses in grammar and lexical variation. Results confirmed that lexical proficiency significantly influences writing performance, particularly in coherence, task completion, and lexical use, though not in grammatical accuracy. The study concludes that the issue lies in limited depth and application of vocabulary, emphasizing the need for integrated instruction linking vocabulary, comprehension, and writing to improve learners’ proficiency.
Harris Padron Campo (Sun,) studied this question.