I won't make myself a broken record by repeating some in these comments, but I'll add to the disagreement here. Or at least partial disagreement. As an ADHD person, I stand to benefit from apps like Duolingo and Habitica, something that engages my monkey brain to be interested in topics I want to be interested in but I don't have the discipline to do or the focus to either. Now, of course, listing those two apps together is a bit misleading as one gamifies learning languages while another gamifies building good habits/discouraging bad ones (whatever those may be for you), but I don't think it detracts from my point.

Now does Duolingo actually succeed at teaching you a language? I will say no, or, at least, not by itself. I will tend to recommend Duolingo either as a beginning tool to get your feet off the ground or with the caveat of "you should also use X, Y, and/or Z tool/study method". (Side note, a: are there any language learning communities on Lemmy, and b: would it be worth creating one on Beehaw if not)