JRR Tolkien invented the pluralization “dwarves”
Tolkien, in addition to establishing the genre of modern fantasy (I’ve just had a lengthy discussion with my English major wife about the legitimacy of this attribution), also created the word “dwarves” as a plural form of “dwarf”. Tolkien explains why in one appendix to LOTR:
It may be observed that in this book as in The Hobbit the form dwarves is used, although the dictionaries tell us that the plural of dwarf is dwarfs. It should be dwarrows (or dwerrows), if singular and plural had each gone its own way down the years, as have man and men, or goose and geese. But we no longer speak of a dwarf as often as we do of a man, or even of a goose, and memories have not been fresh enough among Men to keep hold of a special plural for a race now abandoned to folk-tales, where at least a shadow of truth is preserved, or at last to nonsense-stories in which they have become mere figures of fun. But in the Third Age something of their old character and power is still glimpsed, if already a little dimmed: these are the descendants of the Naugrim of the Elder Days, in whose hearts still burns the ancient fire of Aule the Smith, and the embers smoulder of their long grudge against the Elves; in in whose hands still lives the skill in works of stone that none have surpassed.