In this episode of the Acquired podcast, Luis von Ahn, the co-founder and CEO of Duolingo, shares insights about the language-learning app that boasts over 100 million monthly active users. He attributes Duolingo's remarkable success to its emphasis on user motivation, achieved through gamification elements like short lessons, streaks, notifications, and social features. Von Ahn underscores the significance of a mobile-first design and explains the surprising choice to postpone monetization, which allowed the team to concentrate on user retention and product development. The app's distinctive brand, highlighted by its unexpectedly popular green owl mascot, has also generated substantial earned media, fueling its growth. Additionally, von Ahn talks about Duolingo's foray into subjects beyond languages, such as math and music, the challenge of balancing data-driven strategies with intuition, and the exciting potential of AI to enhance language learning experiences.