app maker

Von Ahn said Duolingo is building a separate language certification app, where people can take a formally proctored exam with a camera and microphone for only $20. And it is expanding its translation business, where publishers pay to have their content quickly translated by language learners — currently CNN and BuzzFeed are the only announced clients.

That casual feeling makes for a broad appeal. “We figured out that we have more people learning language on a given day on Duolingo than in the whole U.S. school system,” von Ahn said.

Nguyen had previously suggested that his life had become overrun by the success of the game, which has achieved a global following despite its basic graphics – often likened to the old Mario Nintendo games – and simple premise of flying a bird past a sequence of pipe obstacles. The revenue from advertising in the game, which is free to download for iOS and Android users, has been estimated at close to £30,000 a day.

Duolingo gets a lot of accolades. It was Apple’s App of the Year in 2013 and on both Google’s editors’ and users’ choice year-end lists. It just won Best Education Startup at the Crunchies. The free language-learning service now has 12.5 million active users.

But its creator has now taken the game offline,  after complaining with a choice of words that sounded more like one of its exasperated players than its maker: “I cannot take this anymore.”

Duolingo CEO Luis von Ahn noted that his product feels different from most other sorts of education experiences. “People say they ‘play Duolingo,’” he said. “Our users aren’t hardcore. They are procrastinating and don’t want to feel as bad, so they open our app.”