Any discussion of computerized language learning is woefully incomplete without a mention of [0], which has an interesting combination of properties.
It is:
* A) run by people who suck at SEO and marketing
* B) technologically and graphic-design wise really janky
* C) harder and less fun than e.g. Duolingo
* and D) drastically, overwhelmingly more effective than every other system I've ever seen at actually teaching you a language (for people with almost all common linguistic-cognition neurotypes aka nearly everyone)
The first 3 attributes mean that almost nobody has heard of it/uses it.
The downside is that for most languages they didn't build out enough curriculum to get you to fluency. It'll take you roughly a third of the way there. I'm building an open source clone (with longer curriculum) for the other two thirds of the way.
Also, L101 should be paired with Yabla, which will train the skill of listening-and-understanding in your target language.
I'm not affiliated with [0] in any way other than by being a happy customer and by the fact that I'm writing an open source clone of their stuff.
[0] https://language101.com/