Has Duolingo helped you to learn German?
Yes, definitely. It helped me a lot, especially because it kept me going and it gave me a great set of vocabulary. When you finish the tree you are then set to go and study from other sources. But even now I keep coming back every day and keep my tree golden and from time to time I encounter a word that I haven't seen for a while from any other source. So it's good.
It is helping me regain knowledge. I had four years of high school German and three semesters of college German, but that was longer ago than I care to admit -- <smile> -- and my skills had deteriorated to almost nothing. DL is great for my purposes, however I am finding that I am now looking for other learning platforms to enhance what I am doing with DL - YouTube videos, and other apps.
It helped me with writing and recognizing words.
The only thing it didn't help me much with is the pronunciation with many words. The program says it so fast, or it is wrong, so I have a German friend, other German apps, and I watch German videos, to make sure my pronunciation is correct.