Duolingo Turkish is a free, game-like Turkish learning system for Web and mobile devices that has taken off like crazy in the last couple of years. It is free and fun - and they put forth that 34 hours of Duolingo practice is equivalent to one semester of university-level Turkish.
Duolingo's free Turkish course is great for beginners and intermediate learners. It teaches you Turkish from step one and plays like a video game - including the addictive part! The learning system is visually stunning with cartoonish graphics and photos to illustrate vocabulary and concepts and help you memorize them.
Most importanly, perhaps, is that it is quite fun and keeps you coming back for more learning. Thus, there is no lack of motivation to learn a language.
Duolingo offers free apps for learning Turkish on iPhone, iPad, iPod Touch and Android devices.