Launched in 2011, Duolingo grew into the most downloaded education app in the world. By late 2024, it boasted 100 million monthly active users, 8 million paid subscribers, and a market capitalization approaching $15 billion. The success stemmed from a gamified approach to learning, use of adaptive AI technology, and alignment of incentives: maintaining a streak on the app not only helped users master a language but also drove subscription growth and reduced costs.

Duolingo had focused almost exclusively on language learning. But the company recognized the enormous potential of Gen AI to power innovative products, such as conversational language practice. Severin Hacker, Co-Founder and Chief Technology Officer, envisioned a future in which AI would transform the app into an educational ecosystem that covered many subjects beyond language, allowing the company to tap into the $56 billion edtech market.

Duolingo had recently started to explore this direction by adding new subjects, such as math and music. HBS Senior Lecturer Jeffrey Rayport and coauthor Nicole Keller join host Brian Kenny to discuss the case “Duolingo: On a Streak” and the long-term benefits and risks of this diversification strategy.