Livemocha - Livemocha is a web application that allows you to learn over 15 foreign languages free of cost.

Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

Bilingua - Bilingua: your language exchange app & learning companion.

Drops - Visual language learning.

My Language Exchange - Language Learning Community for Safe Effective Practice

Clozemaster - Learn a language through mass exposure to useful vocabulary in context.