Did Tolkien's contemporaries know Quenya?

Question

Tolkien famously interacted with several other writers, most notably CS Lewis, as he was working on The Lord of the Rings and his other works. But did any of those writer friends really delve into the languages and history the way he did, or were they mostly interested in his actual publishable stories?

Did Tolkien have anyone, family or friends or professional colleagues, with whom he could discuss the finer points of Quenya and his other languages, maybe even with whom he could communicate using those languages? Or was the linguistic side of Middle Earth a primarily solitary effort?

Answer 1

Christopher Tolkien would have had at least a passing knowledge. He was JRRT's primary collaborator on the Lord of the Rings, he typed much of it, he drew the originally published maps, he was a member of the Inklings and he was familiar with the Silmarillion mythology. There are many references to all of this in JRRT's letters to CT, particularly those from 1944.

From later letters, note in particular number 98:

And anyway my Christopher was my real primary audience, who has read, vetted, and typed all of the new Hobbit, or The Ring, that has been completed. He was dragged off in the middle of making maps.

Letter 105:

But I made a very great effort to finish the Hobbit sequel, and chapters went out to Africa and back to my chief critic and collaborator, Christopher, who is doing the maps.

Letter 115:

For though I have (in the cracks of time!) laboured at these things since about 1914, I have never found anyone but C.S.L. and my Christopher who wanted to read them.