Firstly, discussing "plausibility" is really irrelevant considering we are discussing science fiction. Anything is possible in science fiction, probably why we like it so much.
It is the factual activity of the mind that intrigues me, more than the fiction. If I have destroyed some people's hopes of the merit of this endeavor, I have succeeded. Obviously, there is a real reason why Jeremy is exploring these meanings in his soul, which I could not explain.
And if Tolkien heard his languages "through telepathy" then I am certainly operating at a great disadvantage because I possess no such wonderful gift. I have to do everything the good, ol' fashion way which is through hard work.
The fact of artificial "science fiction" language might be a realm of research. But no scholar can be fooled, to believe that these languages are counterparts of the language they speak. The documentation of the efforts from science fiction fans stands in a realm of non-fiction. In this realm, you are free and prepared to observe how obsurd or accurate our species' philosophical view of ourselves and the universe is becoming.
But I make no reservations when I am simply stating, that unless there is one among us who was raised an elf, like the child of Tyleet, there is really no chance that any of us could teach the elven language. This is similar to the type of experience that J.R.R. Tolkien had gained, in a certain sense.