If only we could find this somehow. Is it really established in the lore somewhere, or is it something new?

It's quite fascinating.

That's not hard. Go to the Imperial Library and search for 'jill' or 'jills'. For the moment it's only in obscure texts (out of game sources) by MK and fan material that they're mentioned as far as I can see.

I like the name. And I, too, think it'll be pronounced like "Yheel" or maybe "Yhil." Or something similar. When I first saw the name on the forum, in another topic's name, I thought it was similar to "jinn." Which, to me, makes it even more interesting. But I guess it is because I speak Arabic, though that's not relevant exactly. What I mean by it is that English isn't my native language and so seeing something like "Jill" doesn't strike me as odd as it does to others.

Though, of course, I don't think any person, on the lore-team, made the distinction between jinn and jill. Or maybe they did, who knows. I already, due to how I viewed the name at first, see it as jinn, and know that in-game, I will continue to associate the two.

I think I mistakenly mixed two things in my mind there.
One the books about king Edward in Daggerfall, where a hero is taught wise lessons by a dragon called Akatosh.
And two, this: http://www.imperial-library.info/content/nu-hatta-sphinxmoth-inquiry-tree,
about the nature of gods.
"A 'jill' is an archaic term for a female dragon. The minute-menders would take on a suitably draconic form."

It seems that Jill isnt a new term, but I dont know enough about how the imperial library works to tell if it pre- or post-dates Oblivion.

The http://imperial-library.info/content/nu-mantia-intercept seems to be the first mention of them:
"Then will mighty Akatosh reply, wherein the petitioner must be demand full freedom! To speak in the fires of time is to render the speaker a subject of the matron Jills, those servants of the Dragon that mend minutes without volunteer. Only through freedom can true words remain untouched."
...
"The Jills did not have their full powers; rather, I should say, all the mundex spirits had every power at every time amendment at every ordering, which is to say none of them could ever fully express; our world was young and so were its architect gods."

It's an obscure text that foretold of the Oblivion Crisis, and was released http://imperial-library.info/ForumArchives/Nu-Mantia_Intercept.html.

So maybe Alduin isn't very good at naming his minions, I dare you to tell that to Alduin's face.

fighting back inappropriate comments on this one is an intense challenge....

Wonder if we'll hear more on Jills.