Interesting, did not know that. He implies (but doesn't say flat-out and it could indeed be a retcon) in the foreword to The Hobbit that it's deliberate:
In English the only correct plural of dwarf is dwarfs, and the adjective
is dwarfish. In this story dwarves and dwarvish are used, but only when
speaking of the ancient people to whom Thorin Oakenshield and his
companions belonged.
I've not heard of any usage of it pre-Tolkien though, and can't find anything obvious after a bit of searching (mostly "dwarvish" turns up Tolkien related things). Anything you can point me to there?
>> In English the only correct plural of dwarf is dwarfs
etymonline points out that the form with a better-in-some-sense claim to be "correct" is dwarrows, not "dwarfs". But that term was uncommon enough that it completely died out. ( http://www.etymonline.com/index.php?term=dwarf )
As I mentioned sidethread, "dwarves" is a natural extension of what happens with other common English words ending in f, making it difficult to argue that it is somehow incorrect.
> etymonline points out that the form with a better-in-some-sense claim to be "correct" is dwarrows, not "dwarfs". But that term was uncommon enough that it completely died out.
That could just as easily be interpreted that he's stuck with this spelling mistake (as he said in the other quote) and now asks us to play along ("that's, uh, just how they talked!").
