Duolingo

Duolingo is a language learning app. Luis von Ahn and Severin Hacker founded it in Pittsburgh in 2011. Von Ahn had earlier built reCAPTCHA, and Duolingo began with an idea to use translation work by learners to translate real web content.

Lessons are short and game-like. Learners earn points, keep daily streaks and move through levels. The app teaches dozens of languages, with English, Spanish and French among the most popular. A green owl named Duo is its mascot and a frequent meme online.

The free version includes ads, while Super Duolingo removes them and adds extras. The company also runs the Duolingo English Test, accepted by many universities as proof of English skills. It added math, music and chess courses, and uses AI for conversation practice. Duolingo went public in 2021. Von Ahn is chief executive. The company has said it will use AI to do more of its content work. Duolingo is based in Pittsburgh and trades on Nasdaq. A large part of its growth has come from marketing on social media.