This new application (Doulingo) will help you if you would like to learn or improve your English. There are lots of easy-to-follow activities that will enhance your oral and written comprehension. You can choose your mother language and the target language from a large list of languages.
According to Wikipedia, Duolingo is a free language-learning and crowdsourced text translation platform. The service is designed so that, as users progress through the lessons, they simultaneously help to translate websites and other documents. As of July 2014, Duolingo offers Latin American Spanish, French, German, Brazilian Portuguese, Italian, and Dutch courses for English speakers, as well as American English for Spanish, French, German, Portuguese, Italian, Dutch, Russian, Polish, Turkish, Hungarian, Romanian, Japanese, Hindi, Indonesian, and Korean speakers.
In January 2014 has 25 million users, out of which about 12.5 million are active.
So, if you are interested, you can get it from the Google Web Store and there are also versions for iOS and Android.