Duolingo is an amazing free app available for iOS and Android and on the web. Duolingo offers courses in English, French, Spanish and other major languages. What is amazing about Duolingo is that it uses an amazing concept to provide you free language courses. While you are learning for free you are also helping them by translating sentences for them for free! It is the best type of quid-pro-quo you will ever find. See the video below to understand better. 

The app is beautifully designed and the lessons are brief and smart and provide an increasing level of difficulty. The app works hard to keep you on track by sending you various reminders and by assigning you points for staying on track. The lessons offer speaking and hearing opportunities as well as the usual multiple choice questions. It really is great!

Duolingo is a great way to invest 5 minutes in a great exercise for your brain the next time you find yourself stuck in a long line or on a train. 

Duolingo is also one of the best examples of how the power of smartphones and crowdsourcing can come together to provide a truly valuable service to us all.