Hi Isabella,
Coincidentally, I’ve used Dolingo to learn Korean before and I have to say it is a great language learning app, and I’m planning to use Duolingo to learn Cantonese in the near future. I think Doulingo is Game-based learning, it motivates us to improve our interest in learning. It allows me to review my past mistakes and then take unit tests to check my learning. Although this is a convenient way to learn, it is not enough to rely on an app, we also need to combine traditional learning methods to make the learning more effective.
Jiajing