The article investigates how easy-to-use and enjoyable mobile language learning apps like Busuu, Duolingo, and Memrise affect the learning process. The researchers interviewed users and kept diaries while using the apps for 10 days. They used Nielsen's Heuristics to analyze the diaries and found a strong link between user experience and the apps' effectiveness. The study suggests that the adapted heuristics used may need improvement for future research. It also recommends evaluating user experience at different stages of app usage in future studies.