Liebnis, Vannia, Indra Perdana, and Elanneri Karani. 2025. “Expediencies of Duolingo in English Language Learning: A Systematic Literature Review”. EJI (English Journal of Indragiri): Studies in Education, Literature, and Linguistics 9 (2):453-62. https://doi.org/10.61672/eji.v9i2.2997.