Yeah, it's an exciting use case. Although all these models, even seemingly GPT-Live-1 doesn't actually hear your pronunciation, it seems they all get passed transcripts, so for learning to speak another language, they're still not there seemingly.
But, it's close! You can control their pronunciation, make them speak slower/faster, and obviously great at anything text, so many use cases work great for language learning with LLMs. Just wish they solved this last mile thing too!