ENGLISH:

Eight grade students at SMP Negeri 5 Pangkalpinang faced challenges in mastering English vocabulary due to a lack of resources and effective learning media. This highlighted the need for interventions, such as using language learning applications like Duolingo. The goal of this study was to discover a significant difference by comparing students who used Duolingo and those who did not in the eighth grade at SMP Negeri 5 Pangkalpinang.

This study employed quantitative method which was a quasi-experimental design and was conducted at SMP Negeri 5 Pangkalpinang. The sampling technique used was non-probability sampling, specifically purposive sampling. The study focused on four types of words: nouns, verbs, adjectives, and adverbs.

The result of the statistic calculation showed that the value of tcount = 2,73, it was higher than the ttable = 2,08. Therefore, the null hypothesis (H0) was rejected and alternative hypothesis (Ha) was accepted. Thus, there was significant difference between students’ vocabulary mastery taught by using Duolingo and those who were not. In conclusion, the use of Duolingo had significant effect on students' vocabulary mastery.