App for tracking your progress at learning another language

I thought an app like Duolingo would be great for tracking your progress learning another language. It gives you tasks to accomplish each day and rewards you for completing them, which is a great way to motivate yourself to learn something if you're not good at doing that. I would also want the app to be able to detect if you're speaking the language properly. If you can't get the app to detect what you mean it should let you know and allow you to try again.