My latest reading is a scholarly anthology called Language Invention in Linguistics Pedagogy, ed Jeffrey Punske et al (OUP, 2020). I'm not recommending this to you - for one thing, it's rare enough that I had to get it by inter-library loan from a university 2000 miles away - but it struck some interesting thoughts.
It's a book that kept turning up when I was searching for Tolkien references in the 2020 literature for my bibliography, so I had to look at it to see if there was enough about Tolkien in it to make it worth listing. There isn't, but he's frequently referred to. The topic is using invented or constructed languages ("conlangs" is the accepted term) in linguistics courses, and most of the contributions are by professors or college instructors reporting on classes they've taught. Often this involves having the students construct their own languages, but most of the classes begin with surveys of existing conlangs, and Tolkien's Elven tongues are always mentioned.
There are also frequent citations to Tolkien's essay A Secret Vice, an early and extensive discussion of the motivation for and practice of creating artistic conlangs, and several authors cite that Tolkien's "novels were developed in order to situate his invented languages in a time and place ... Thus, while other writers created conlangs for their fiction, Tolkien created fiction for his conlangs." Tolkien did say something like this ("The invention of languages is the foundation. The 'stories' were made rather to provide a world for the languages than the reverse"), but to present it baldly, as these writers do, and without the context Tolkien's statement is embedded in, does rather oversimplify the process.
I found the most interesting chapter to be Arika Okrent's (a linguistics PhD but a journalist, not a professor) on how budding linguists find and develop their love for languages, and how they're distinct from other language students. Linguists are attracted by the structure and grammar of languages, not so much by the opportunity to read literature in that language, which is the customary motivation. Indeed, linguists who major in a specific language often find themselves hitting a brick wall with the analysis in their literature classes, which they find alienating. One French major tells of a class on Stendhal's The Red and the Black. He was asked "Why do you think Julien Sorel took the hand of Madame Renal?" and he says he wishes he had the nerve to reply, "I have no idea, but what I want to know is, why he used the subjunctive?"
I found I could identify with this, but only to an extent. I'm not a linguist, I'm linguistics-adjacent. I took Spanish and German in school (I switched to German because it was fun to pronounce and in hopes of reading the liner notes on German classical LPs), but I found memorizing vocabulary to be nerve-wracking, and I never got fluent enough to take literature classes in it. (But I hated the Leavisite dogma I was getting in my English lit classes, so I doubt I would have done well.) So while I was actually pretty good at language, I disliked learning the topic, which is also how I stood with mathematics.
I majored in history at university; sticking mostly with American history meant that other languages didn't come up much. UC had a linguistics department, but it didn't occur to me to check it out until I took the basic intro course in my senior year. Surprise, I loved it. It wasn't about languages and the drill of memorizing them, it was about language, the concept, and the structural comparison among lots of languages which you studied on that level, but that you weren't expected to know well enough to speak or to read fluently. This was much more interesting than studying one individual language in detail. I learned enough about linguistic theory to disagree with Noam Chomsky, and a lot else.
I could have done with more of that, but it was too late. If I'd discovered this in my freshman year and the follow-up courses had been equally enticing, I might have changed my intended major, who knows?