Did you know that J.R.R. Tolkien's favorite book was a volume on Finnish grammar?
Tolkien was a philologist--an arcane field of study, both in Tolkien's time and ours.
The author of The Hobbit and The Lord of the Rings was primarily interested in obscure, dead European languages like Anglo-Saxon and Old Norse.
Tolkien's interest in languages is obvious to anyone who has ever read his books. More details in the video below: