Okay, so my friend Chloe just pointed this out, and it’s amazingly accurate:
“Because of the scarcity of Dwarf-women, their secrecy and similarity in appearance to males, and their lack of mention, many Men failed to recognize their existence.”
Well, Tolkien was a philologist, and a Norsist, and that means he knew Völuspá well enough to pull the names of every dwarf from Dvergatal and he had a pretty firm grasp Old Norse grammar.
In fact, he grasped it well enough that he knew if you dropped an n from a name ending in -inn, it changes from the masculine definite enclitic to the feminine.
Well, what the hell does any of this mean?
Well, I give you the names of the Dwarves from the Hobbit, as they appear in Dvergatal (stanzas 14-16) and in the order they appear:
Dvalins,* Dáinn, Bívurr, Bávurr, Bömburr, Nóri, Óinn, Þorinn, Þráinn, Fíli, Kíli, Glóinn, Dóri, Óri
Now, in the Hobbit, they’re named as follows:
Dwalin, Dáin, Bifur, Bofur, Bombur, Nori, Óin, Thorin, Thráin, Fíli, Kíli, Glóin, Dori, Ori.
Now, you notice something with the way those names got changed? That’s right, he changed the masculine -inn definite suffix to -in, which is feminine.**
That means that, at least grammatically, Dwalin, Dáin, Thorin, Thráin, and Glóin are female Dwarves.
Since we know Tolkien was meticulous about his grammar, this was done most likely as an in-joke (lol we’re so learnèd about Norse grammar that my comment on Dwarf women being indistinguishable from men is hilarious because of this grammatical funniness)
But there’s a not-inconceivable chance that the Dwarves were using the masculine pronouns in Westron because that’s what the Men who met them used, despite the fact that a third of the company was female, and hey, it’s kinda neat to think he wrote a bunch of Dwarf-ladies going on an adventure.
*-ins is the masculine Genitive definite article suffix in Old Norse
**He also dropped the double-r suffix, but -r as the root is still, in general, a masculine grammatical feature
