Use and development of applications for smartphones (so-called 'apps') continue to rise, and it comes as no surprise that language learning apps (such as Google Translate) are immensely popular among the younger generation. But, do these apps actual help students learn a language and, if so, how is apps usage influenced by the proficiency of the language learner? Our research focused on the use of apps related to language learning in two major Korean universities. Koreans are known to be high-tech users and avid language learners, and Korea can therefore provide a good model for how education and technology intersect. We asked students studying German, Swahili, Hausa, and Zulu to inform us about the role that smartphone apps play in their language learning, both at home and in a formal education setting (e.g., classroom). Results showed that one important determiner for how apps were used was language proficiency. We further found an interaction effect between proficiency in English and the other languages, which directly impacted app use. Our findings suggest that these rather sophisticated digital and language learning students make sophisticated choices of apps based on knowledge of apps and the language learning task at hand.