Duolingo is a catch-all for many different languages, but the didactics are rather meh. There are dedicated sites for different languages, less well-known than Duolingo & therefore harder to find. For Japanese, there’s wanikani.com for example. I’d suggest joining a community for learning one specific language and ask what learning tools & materials the others use.
It also depends on what type of learner you are + your level of motivation/your goals: Do you want to achieve fluency or are you already content with just a passive understanding, do you want oral AND written command of a language, etc.
Duolingo is a catch-all for many different languages, but the didactics are rather meh. There are dedicated sites for different languages, less well-known than Duolingo & therefore harder to find. For Japanese, there’s wanikani.com for example. I’d suggest joining a community for learning one specific language and ask what learning tools & materials the others use.
It also depends on what type of learner you are + your level of motivation/your goals: Do you want to achieve fluency or are you already content with just a passive understanding, do you want oral AND written command of a language, etc.