Elon.io offers fast-paced AI generated language courses that have indefinite depth, because they automatically continue growing as you learn.
Even though there's a paid option for dark mode, statistics and AI interactions, all content is freely available, unlimited.
I've launched 25 AI-generated language courses. The main distinguishing features are that they're really fast-paced and unlimited in depth.
The courses are freely available. In the paid version you can ask more questions to the AI.
