THE EFFECTS OF VOCABULARY AND GRAMMAR MASTERY TOWARDS STUDENTS’ SKILLS IN READING EXPOSITORY TEXTS

Abstract

This study examines the effects of vocabulary mastery and grammar mastery on students’ ability to read expository texts. The research employed a quantitative survey design using multiple regression analysis. The participants consisted of 85 students from two state senior high schools in East Jakarta selected through random sampling. Data were collected through three instruments: a vocabulary mastery test, a grammar mastery test, and a reading comprehension test focusing on expository texts. The data were analyzed using descriptive statistics and multiple regression analysis with the help of SPSS version 22. The results indicate that vocabulary mastery and grammar mastery simultaneously have a significant effect on students’ reading skills (Sig = 0.000 < 0.05; F = 33.734). The coefficient of determination (R² = 0.451) shows that both variables contribute 45.1% to students’ reading skills. Individually, vocabulary mastery contributes 20.66%, while grammar mastery contributes 24.44%. These findings highlight the importance of strengthening students’ vocabulary knowledge and grammatical competence in improving reading comprehension.