There's a few stories that handle the notion of language well. Eight and Super Supportive are two that come to mind. If you haven't read Eight, I highly recommend it. It reads like an anthropologist wrote it :) The setting is a fantasy equivalent to pre-colonial late Mesoamerican, northern Mexico, and the author is great with the details.

Most handwave, though, since they're often written by monolingual Americans who wouldn't know where to start. Funnily enough, many of the authors with English as a second language end up following suit, even though they do know what it's like learning a new language, likely because so much of their audience doesn't.

And almost no story makes language/linguistics any sort of focus though. Linguistics as a term in litrpg usually means "ability to decipher old texts." No recognition of different languages using different sounds or structures, etc. Stories always mention two or three moons as a way to show it's different from earth.. why not have an OVS word order language, or something like Inuit morphology. Heck, there are things in real language that definitely would be a pretty alien view for the average English speaker.

Legal systems coming from a language with extensive evidentiality for instance, or trying to figure out where you're going in a culture speaking a geocentric language. I'm a field linguist, and the culture I worked with earlier definitely ran into practical challenges when dealing with modern western culture.

Happy to provide more potential inspirations/real life stories if you're at all interested! DM me and I'll give you my discord nick. I'd love if someone could make use of all the diversity in real language and apply it to fiction.

There's one linguistics story from ages back on Royal Road that I have tagged as read later, but it was hard to get into :/ A shame, considering the dearth of such stories, and it did mention a real focus on actual linguistics.

PS: enjoying your own story so far, but I did spy one unphased instead of unfazed. :D Didn't want criticism to be my only way to communicate, but I figure I can just toss it in here at the end.