Duolingo: translating the Web for free

This is the question that computer scientist Louis von Ahn and his team had been asking themselves for a while. The solution they have come up with has the double merit of being both free and educational. In an ingenious way they propose to combine translation with the ambition of many people: language learning. At TEDxCMU, Louis von Ahn shares how his ambitious new project, Duolingo, will help millions learn a new language while translating the Web quickly and accurately - all for free. Louis von Ahn is an associate professor of Computer Science at Carnegie Mellon University, and he's at the forefront of the crowdsourcing craze.