The famously-inconsistent rules of English. I was writing about something the other day in a fantasy setting, and I wanted to refer to the language spoken by elves.

In English, the various types of people (British, German, Japanese, etc.) all get a capital letter. By extension the languages also do. However, non-humans like cats and dogs don't get the capital. Even the 'clever' species like dolphins don't get a capital; it seems to only be humans (although the word "humans" itself doesn't get one).

So, presumably, elves don't get a capital E. What about their language? Elvish or elvish? I did some searching and there doesn't seem to be an accepted rule for this sort of thing; apparently even Tolkien switches back and forth in his books, seemingly at random!

I ended up deciding on "elvish" with a small E, because it isn't a name... and was then able to forget all about it until I was just reminded by someone talking about addressing rats in another thread :)