The mine in Karthwasten seems to have multiple spellings:

• ES Wikia: Sanaurach Mine
• Quest: Convince Atar to leave Sauranach Mine
• Quest: Convince Ainethach to sell Saunaruch Mine
• UESP: Sanuarach Mine (thanks, Turija)

Am I missing something? They all contain the same letters, just in a different order - are the different spellings intentional?

As always, take anything you read on Wikia with a huge grain of salt.

The Wiki spelling seems to be the one used elsewhere on the web too.

And that still doesn't explain the two in-game spellings...

The UESP has a different spelling than any of the three listed in the OP. http://www.uesp.net/wiki/Skyrim:Sanuarach_Mine_(quest)

What is going on?!

This sort of thing happens from time to time in Bethesda's games. I seem to recall a few variant spellings of things back in Morrowind too. I think we just have to accept some of these as part of the "charm" of a Bethesda game.

It's not a "bug", it is a "feature!"

Probably just carelessness by Beth and both wiki sites. I never would have noticed if you hadn't pointed it out.

Mila Valentia is actually named MilaValentinaREF in the CK. There are all sorts of typos like that, even in the game.

It might be deliberate - only in our modern world are there standardised spellings and grammars in language. Even nowadays, certain minority languages - e.g. Sicilian - aren't standardised. It is naturalistic for there to be different spellings.

Of course, these could all be errors and completely unintended.

Agreed, let's go with "feature" Haha.

I'm a pedant (and a writer)

Maybe a slightly idealistic view but I'm willing to go along with it. Damn Skyrim for not having any actual schools to teach literacy!