How Duolingo’s CEO harnessed our game addiction for good

You already know Luis von Ahn’s work. He helped create CAPTCHA, the technology that helps control spam on the internet and crowd-sources humans to help computers read and digitize old text. In 2012, he co-founded Duolingo, a free language learning app. To him, the app was meant to solve “this mismatch where most of the people trying to learn a language didn’t have $1,000, whereas the software that would teach you a language cost about $1,000.” Von Ahn says there are now more Americans learning on his app than there are in the public school system. Why? Because Duolingo works like a video game.