Duolingo, the free, wildly popular language app, is taking its zero-ad, gamification approach to learning into the classroom today, with the launch of a new platform called Duolingo for Schools. Launched in 2012, Duolingo offers reading, listening, speaking and writing exercises split into different lessons ("skills") and levels (if you get a certain number wrong in a given level, you lose a life). Good example of how free app available on line are helping to solve the financial factor on developing countries and improving language learning.