Duolingo

Duolingo, founded in 2011 by Luis von Ahn and Severin Hacker, has grown from a Carnegie Mellon research project into the world's most downloaded education app. Headquartered in Pittsburgh, the platform teaches over 40 languages through a gamified system of short, daily lessons. Its signature green owl, Duo, sends persistent reminders that have turned into a beloved internet meme. The app's freemium model keeps core lessons free, with ads supporting the service, while Super Duolingo removes ads and adds perks like unlimited hearts and offline access.

Beyond languages, Duolingo has expanded into math (Duolingo Math), music, and literacy (Duolingo ABC). The Duolingo English Test, launched in 2016, offers an affordable online proficiency exam accepted by thousands of universities, with results in two days. The company went public on NASDAQ in 2021 under the ticker DUOL, and by 2024 had surpassed 500 million downloads. Its adaptive learning algorithm and spaced repetition system have made it a leader in edtech, though critics note it works best for beginners and intermediate learners.

In August 2026, Duolingo acquired Animade, a London-based animation studio, to enhance its motion design and storytelling. That same month, Sallie Krawcheck, former Citigroup CFO, joined the board, signaling a focus on financial strategy. Despite a soft revenue outlook that year, analysts saw potential undervaluation, and user retention hit all-time highs. Duolingo's cultural footprint extends far beyond the app, with viral marketing and a dedicated fanbase that treats language learning as a shared, playful experience. [edit]