The beginner textbooks I've used have accompanying CDs, and also audio available on their websites. The best beginner listening practice is to focus on minimal pairs so that you can start to hear the difference between different sounds that originally sounded the same. Some textbooks include this (I remember having to combine initials and finals in Chinese with my teacher)

For speaking, Duolingo speech recognition isn't very good and is not going to provide specific feedback for improving your pronunciation. I'm not even a fan of practicing pronunciation virtually with a live tutor. I have found in person pronunciation practice to be very valuable compared to doing the same thing but online. A textbook doesn't solve this and neither does Duolingo.

They are also boring to the extreme and don't bite size it for you. They are also unpactical format- fiddling with cd requires you to be at home and have cd player available when you want to learn. So basically you have to be near laptop.

I don't know anyone who did stick with textbook approach long enough to learn something.