THE EFFECTIVENESS OF DUOLINGO FOR STUDYING VOCABULARY OF THE STUDENTS X E3 AT SMA NEGERI 3 SAMPIT

Khoirunnisaa Afiifah Hanun (NIM: 201910100311003).The Effectiveness of Duolingo for Studying Vocabulary of the Students X E3 at SMA Negeri 3 Sampit. Thesis English Education, Faculty of Teacher Training and Education, University of Muhammadiyah Malang, 2025.
The purpose of this study is to find out factual data on the effectiveness of using the Duolingo application on students' vocabulary mastery. This study used a quasi-experimental research method. To conduct this research, 68 total students from classes XE 1 and XE 3 of SMA Negeri 3 Sampit in the academic year 2024/2025 were selected as samples in this study. They were XE 1 as the control class and XE 3 as the experimental class. Each class consisted of 34 students. Duolingo application was used as an assistive learning media in the experimental class, while the control class received material presentation from the teacher, assignments, and some quizzes. Based on the results of the calculation, the average post-test score of the experimental class was 82.85 while the control class was 76.26. The results of statistical hypothesis testing using the independent T-test show that at the 5% significance level (α = 0.05), t observe is 3.92 while t table is 1.99 or t observe > t table. Therefore, H0 is rejected and Ha is accepted. Furthermore, Cohen's formulation was used in measuring the effectiveness of using the Duolingo application, and the result was 1.28. The results of this study indicate that the use of the Duolingo application is effective in students' vocabulary mastery and has an influence on students of class XE 3 SMA Negeri 3 Sampit in the academic year 2024/2025.