Vocabulary mastery is categorized as the base component of language learning. In this current state, there are
many learning tools which can help EFL learners rising their vocabulary mastery, one of which is Artificial
Intelligence (AI). Artificial intelligence tools are software applications or systems that employ AI technology to
carry out tasks that often call for human intelligence. Duolingo is one of artificial intelligence tool that can be
implemented in language learning in mastering vocabulary. Hence, the aim of this study is to investigate student
perceptions on upgrading vocabulary mastery through Duolingo as learning tools. Student perceptions in this
study are divided into three factors (perceptions, attitude, experience). Mixed method is implemented on this
investigation to analyzes the data. Data was collected through questionnaire as numeric data and interview as
qualitative. The numeric data was analyzed through descriptive statistic, while the qualitative data was analyzed
through qualitative analysis. The findings indicate a strong positive perception that Duolingo has crucial role on
improving student vocabulary mastery. Duolingo app features such as leaderboards, challenges, achievement
systems, and feedback features that enable students to learn independently are things that influence students to
help them master English vocabulary. On the other hand, the ease of using these features in the Duolingo
application also supports the development of their language skills. Thus, it can be concluded that students'
perceptions of the application of the Duolingo application in learning English to enrich their vocabulary are very
positive and good.
Keywords: Student