Not a duolingo alternative, but I recently built a (WIP) web app for journaling in your target language with LLM-powered feedback and in-context word discovery.

I built it for myself as I wanted to practice writing in my target languages, while also wanting to learn new words... The idea was that hopefully I would remember the words if I could associate them to my journal for that day.

It's a little clunky, but give it a go if you're interested!

Right now it's a bring-your-own claude token model, but let me know if you're not comfortable with that.

https://lingolog.app/