If i may offer a reading suggestion: J.R.R. Tolkien: Author of the Century by Tom Shippey.

Found it at my local library, so shouldn't be too hard to access. And I was thoroughly impressed by his work. Delves quite a ways into Tolkien's original reasons for starting the book, much of which involved a desire to recreate the lost mythologies and histories and language of the Germanic peoples and especially those of whom migrated to England. Tolkien's profession as a philologist is expounded upon, and I learned a lot about philology in general and the ways in which Tolkien utilized it for his work.

Unfortunately, that was in another city, and my notes are not readily accessible. But, I will attempt to locate them...because the information therein was truly fascinating.

Sadly I don't have an answer but if you can't get any answers here you could try /r/tolkienfans.