DUOLINGO

Luis von Ahn is a Guatemalan computer scientist who previously created CAPTCHA and reCAPTCHA (sold to Google). He noticed that millions of people wanted to learn a new language but could not afford Rosetta Stone ($500+) or private tutors.

He teamed up with his PhD student Severin Hacker at Carnegie Mellon to build a free language learning platform. The initial concept was to use language translation as a way to crowdsource the translation of the web — users learned by translating real sentences.

That model evolved into the pure gamified learning app we know today.

Duolingo is a freemium language learning app. The core product is free with ads.

Revenue comes from Duolingo Plus subscriptions ($7-14/month for ad-free, offline access, unlimited hearts), in-app purchases (gems, streak freezes), and the Duolingo English Test (a standardized test accepted by 5,000+ institutions as an alternative to TOEFL). Advertising is the secondary revenue stream.

The app uses gamification — streaks, XP, leagues, hearts — to keep users coming back daily.

Duolingo (language learning, 40+ languages), Duolingo Plus (premium subscription), Duolingo English Test (standardized testing), Duolingo Math, Duolingo Music, Duolingo ABC (kids literacy)

Double down on gamification — Duolingo treats engagement metrics like a mobile gaming company, not an education company. Expand beyond languages into math (Duolingo Math) and music (Duolingo Music).

Grow the Duolingo English Test as a cheaper, faster alternative to TOEFL/IELTS. Use AI (GPT-4 integration) to add conversation practice and personalized tutoring for subscribers.

Proving that a free education app can be a real business. For years, skeptics questioned whether Duolingo could monetize effectively — free users vastly outnumber subscribers.

The company proved it could by making the free experience slightly annoying (ads, limited hearts) while making the paid experience smooth. The other challenge: proving that gamified learning actually teaches people something meaningful, not just how to maintain a streak.

Union Square Ventures, Kleiner Perkins, CapitalG (Google), New Enterprise Associates, Durable Capital Partners, public market investors