Students’ Use of ChatGPT in Relation to Their Vocabulary Skills and Writing Proficiency

ChatGPT is an advanced AI language model increasingly used by students as a tool for language learning and academic support. This study explored the relationship between students' use of ChatGPT and their vocabulary and writing proficiency. It employed a descriptive-correlational research design and involved 50 Grade 8 students from one of the higher education institutions in Ozamiz City, Philippines, selected using a design-based purposive sampling method. Three instruments were used: a ChatGPT Usage Questionnaire, a Vocabulary Skills Assessment, and an English Writing Proficiency Test. Data were analyzed using Mean, Standard Deviation, and Pearson Product-Moment Correlation Coefficient. The findings revealed a very high level of ChatGPT use, particularly for language learning tasks. The students showed high level of vocabulary skills and very high writing proficiency, especially in coherence, grammar, creative expression, and content. However, there was no significant relationship between ChatGPT use and vocabulary skills. No significant relationship was also noted between use of ChatGPT and their writing proficiency except for creative expression. While ChatGPT may not directly enhance technical language skills, it could positively influence students’ creativity and originality in writing. Integrating AI tools like ChatGPT into writing instruction as supplementary support to encourage imaginative expression while emphasizing guided learning for vocabulary and grammar development. Educators, curriculum developers, and school leaders should promote structured, ethical ChatGPT use by integrating AI literacy, training teachers, and sustaining direct instruction in vocabulary and grammar to support creativity and academic writing.