Duolingo is my new favorite web service. It makes learning a new language accessible and the best part is that it’s free! Their iOS app is consistent with their web presence, easy to use, and has just the right number of interactive elements that let you learn without cluttering your screen. It’s also super smooth to use. No icky lagging business like most apps out there.
You lose hearts if you make a mistake and if you lose all hearts you have to start all over again. One type of question is listening to a sentence and typing it out in your default language. Notice the appropriately designed turtle icon for playing the sentence slower.