realistically if someone were to try and seriously learn a language they would need to use a textbook and workbook alongside some memorisation tool like anki
luodingo explains NOTHING! but it may be kinda useful if ur learning a language thats grammatically really close to your native language
duo is way better than my spanish classes because irl they just assume you've memorized everything from every previous unit and move on while duo goes back to random previous units and your weakest topics so you're able to consistently learn everything
luodingo explains NOTHING! but it may be kinda useful if ur learning a language thats grammatically really close to your native language