I’ve been using Duolingo to learn a language for a few years now, enjoy it, and feel that I continue to progress. I know there are other apps out there as well but I don’t have any experience with them. Duo does have a gamification component to it — some of which you can disable, but not all — and there is a cost if you choose to subscribe.
For me, though, I’m likely going to need to immerse myself and/or take a few formal classes to get better at conversational speaking as I keep learning. Not many folks around me learning German. The app does help practice conversations and give tips, which is nice, but using a language in real life with another person is more effective for me.