This study aims to determine the significant impact of the Duolingo application and
students' perceptions regarding English vocabulary mastery at SMPN 3 Candi. The
research employed a pre-experimental design, specifically a one-group experiment, to
explore the effectiveness of the Duolingo application in enhancing seventh-grade
students vocabulary at SMPN 3 Candi. The study methodology consisted of pre-test,
treatment, and post-test phases. The study focused on seventh-grade students at SMP
Negeri 3 Candi. The simple Random Sampling Technique was used to select the sample
for this research. In determining the sample, researchers utilized a lottery technique.
The sample size was determined by dividing the seventh-grade student population of
288 from eight classes, resulting in 36 students with each class requiring 4-5 students.
Based on the research findings, the use of the Duolingo application significantly
improved English vocabulary mastery among seventh-grade students at SMP Negeri 3
Candi. These findings were supported by increased test scores, statistical analysis
showing significant differences, and positive student perceptions and engagement with
Duolingo. This confirms the effectiveness of Duolingo as an enjoyable and effective
vocabulary-learning tool.