León Abad, ElianaHerrera Paredes, Ximena del Rosario2025-03-252025-03-252025-03-25Herrera Paredes, Ximena del Rosario (2025). The use of Duolingo to improve vocabulary skills in 8th graders. La Libertad. UPSE, Matriz. Instituto de Postgrado. 74p.UPSE-MPI-2025-0009https://repositorio.upse.edu.ec/handle/46000/13387The research aims to improve the English vocabulary proficiency of eighth-grade students at a private school located north of Quito. Several factors hinder students from enhancing their English vocabulary; one significant factor is their age, specifically preadolescence, during which emotional changes can occur. Additionally, the traditional methods of teaching and learning a second language may contribute to this issue. To address this problem, the researcher intends to utilize the Duolingo application, a modern online tool that can facilitate vocabulary mastery. The study aims to explore the effectiveness of the Duolingo application in improving vocabulary among young students. This study used a pre-experimental design that included both pre-test and post- test groups. The pre-test was given before the intervention to evaluate the students' initial vocabulary proficiency. At the same time, the post-test was administered after the intervention to assess vocabulary mastery achieved as a result of the intervention. The study focused on a population of eighth-grade students, with a sample selected from eighth-grade A, which consisted of 33 students. The results revealed a significant difference between the pre-test and the post-test scores. The mean score for the pre-test was 6.05, while the mean score for the post-test was 7.70. This reflects a vocabulary increase of 124% for the Experimental Group. Based on these results, the researcher concluded that the use of the Duolingo application effectively improved the vocabulary mastery of eighth-grade students at this private institution.engopenAccessAtribución-NoComercial-SinDerivadas 3.0 Ecuadorhttp://creativecommons.org/licenses/by-nc-nd/3.0/ec/ADOLESCENCEVOCABULARYDUOLINGO APPLICATIONmasterThesis