Duolingo

Duolingo is a language learning app that is structured like a game and uses spaced repetition technology. To keep learners motivated, Duolingo features leaderboards, daily goals, and rewards such as badges, items, its own currency, and experience points. On September 24, 2024, Duolingo introduced a new lesson type called "Adventures," where you can control one of Duolingo's mascots and answer questions at the same time to advance the scene. In April 2025, Duolingo added a chess course for iOS.