THE EFFECT OF USING VOCABULARY.COM ON STUDENTS’ VOCABULARY MASTERY IN EFL CLASSROOM (An Experimental Research at 10th Grade of SMK PGRI 2 Taman in Academic Year 2024/2025)

Abstract

ABSTRACT DESTIANTI, RISKI DWI AYU. 2026. The Effect of Using Vocabulary.com on Students’ Vocabulary Mastery in EFL Classroom (An Experimental Research at the 10th Grade of SMK PGRI 2 Taman in Academic Year 2024/2025). Research Project. English Department. Faculty of Teacher Training and Education, Universitas Pancasakti Tegal, The First Advisor is Dr. Sumartono, M.Pd, and The Second Advisor is Fajar Prihatini, M.Pd. Key Words: Vocabulary.com, Vocabulary Mastery, EFL Students, Quasi-Experimental Design, Learning Media. The study aims to investigates the effect of using Vocabulary.com on students’ vocabulary mastery in the EFL classroom. The research was conducted at SMK PGRI 2 Taman in the academic year 2024/2025, involving tenth-grade students. The objectives of this study were to examine whether the use of Vocabulary.com significantly improves students’ vocabulary mastery and to identify students’ responses toward its implementation in vocabulary learning. This study employed a quantitative approach using a quasi-experimental pre-test and post-test control group design. The sample consisted of 60 students selected through purposive sampling, divided into an experimental group (30 students) and a control group (30 students). The experimental group received vocabulary instruction through Vocabulary.com, while the control group was taught using conventional methods. The data were collected through vocabulary tests and a questionnaire, and analyzed using descriptive statistics, paired-sample t-tests, and independent-sample t-tests. Data were collected through vocabulary tests and a questionnaire, and analyzed using descriptive statistics, paired-sample t-tests, and independent-sample t-tests. The results revealed that there was a statistically significant difference between the pre-test and post-test scores of the experimental group (p < 0.05). Furthermore, the experimental group outperformed the control group in post-test results, indicating that the use of Vocabulary.com had a significant positive effect on students’ vocabulary mastery. The questionnaire findings also showed positive student responses in terms of motivation, engagement, and ease of learning. In conclusion, Vocabulary.com is an effective digital learning tool for enhancing vocabulary mastery among EFL students and can be recommended as an alternative instructional medium in vocabulary teaching