Duolingo is a great example of gamification done well, I'd argue that's the whole selling point of it! I'll also say it was useful for me to learn basic German

Duolingo is a great example of gamification done well, I'd argue that's the whole selling point of it! I'll also say it was useful for me to learn basic German for a trip to Germany, 6 months of Duolingo + a few extra (beginner) books do wonders