[zwayhowder]

I haven't looked at Duolingo for a while, I tried it for Polish about 4 years ago and it seemed ok.

I've used a lot of tools over the years for Korean, Japanese & Mandarin, all are ok, but I usually go back to Anki for pure flash cards.

The only exception was Memrise for Japanese that I used for several years because everyone in my original class signed up at the same time and we were all "friends" on it so the competitive nature in us kicked in. IIRC Duo has a similar feature, but the challenge is getting that initial social pressure going. Once my cohort dropped off Memrise, so did I.