[Mirioron]

English is not my first language. We had 11 years of 4-7 hours of English a week, yet this was still not enough to get everyone to be decent at the language by the end of high school. The people who used English to play video games or chat online tended to be much better at it than others.

What I've realized is that experience teaches you to speak, read, and write a new language. You need a lot of experience to become good at it, because the language has to feel intuitive if you want to hold a conversation in it. There's the recommendation that if you want to learn a language you should immerse yourself in it (in real life). I think the reason why that works is because it forces you to figure out how to use the language and gives you an immense amount of experience in it.

I think that Duolingo is just another way to get slightly more experience in the language, but it's probably not going to be enough on its own. You're just not going to be spending hours every day on it to compete with language classes. From my experience, it was a nice way to quickly learn some of the basics of Japanese, but Duolingo really can't make you understand Kanji more easily than other methods.