THE CONTRIBUTION OF VOCABULARY MASTERY TO SPEAKING PROFICIENCY (AT SMPN 1 KLUET SELATAN)

This study investigated the contribution of vocabulary mastery to the speaking ability of seventh grade students at SMPN 1 Kluet Selatan. Based on this focus, this study addressed two main questions (1) Is there a significant correlation between vocabulary mastery and students' speaking ability and (2) Does vocabulary mastery contribute to students' speaking ability. Using a quantitative correlational design, this study involved 46 randomly selected students who were assessed using two instruments: a multiple-choice vocabulary test and a speaking performance test conducted in the form of a dialogue. The collected data were analyzed using Pearson Product Moment correlation, simple regression analysis, and hypothesis testing to determine the relationship and contribution of vocabulary mastery to speaking ability The results reveal a very strong and statistically significant correlation between vocabulary mastery and speaking proficiency, with a correlation coefficient (r) of 0.809 and a p-value of 9.8 × 10⁻ ¹² (< 0.05). The regression analysis shows that vocabulary mastery contributes 66% (R² = 0.655) to the variability in students’ speaking scores, with the regression model Y = 30.95 + 1.78X indicating that every one-point increase in vocabulary score raises the speaking score by 1.78 points. Hypothesis testing confirms the significance of this contribution, rejecting the null hypothesis and accepting the alternative hypothesis. These findings suggest that vocabulary mastery plays a critical role in developing students’ speaking skills and should therefore be prioritized in English instruction, especially at the junior high school level. This study also contributes to the body of research by offering empirical evidence from a younger learner demographic and providing practical insights for educators in curriculum design and instructional strategies.