At least in the grassroots language learner community, there seems to be a growing sense that the most efficient way to achieve real fluency in a second language is: regular long-term effort to read or listen to text or media in the language that is just a little above your level of understanding. Notably different from how duolingo works.

https://en.wikipedia.org/wiki/Input_hypothesis

I suggest that the power of these new language models is that instead of finding “the path of success“ the models can adapt, and learn to accommodate individuals with every respective path to success. Chat, GPT never has the same conversation with two different individuals, roughly speaking. If Duolingo can pivot to deliver automated, personalized learning experiences, then more power to them. That would be fantastic in my opinion.

It's pretty clear immersion is the best path.

Using AIs conversational skills seems like the best way to employ AI in language learning.

Immersion will absolutely get you speaking and listening fluency (with enough time). Reading and writing? That's another matter. If you're coming from a Latin alphabet language and trying to learn to read and write Chinese or Japanese then you've got a lot of study and practice ahead of you. Acquiring the knowledge of several thousand Chinese characters (needed for both languages) can only be done through deliberate study.

> what the most efficient path to learning a new language is.

This is assuming that there is a "most efficient path to learning a new language" that applies to everyone.

That's the nice thing about ai though, it could be tailored to your experience and learn so you do. For example if you are progressing on pace with similar learners it could apply a different learning program or vary course materials until it sees improvement