Re: Dwarfs or dwarves?
Checked that other site - they didn't provide the "real" reason:
In the middle ages, possibly up until the mid-late 19th Century, depending on font, the letter "s" was shaped more like an f.
This meant dwarfs looked more like dwarff (and all the other words that ended with f, when pluralized, kinda looked like they ended with ff).
Because of this ambiguity, changing what looked like ff to vef (dwarvef) made things much less ambiguous. However, once the common fonts made s look like the modern s, the "fix" was no longer needed. Unfortunately, the language rules are harder to change, these days, so no one bothered.