I was watching the end of a House MD rerun and I got lost regarding the plot. So I looked online for the script and found it pretty easily. Reading through it I came across the following lines. A young girl (Kama) is asking the doctor (Foreman) about her brother's prognosis:
KAMA: Is he gonna die?
[Foreman looks at her.]
FOREMAN: No. No one's gonna die.
KAMA: [smart-ass] In the whole world ever? That's so great.
FOREMAN: [chuckles] I meant...
KAMA: I know what you meant. But I also know bad things do happen. My dad always had a few drinks whenever he went out. Always said it'd be okay to drive. [shrugs sadly] Until it wasn't. I would just like some mourning this time.
[Foreman looks at Kama, sympathetically.]
FOREMAN: We're nowhere near anything like that happening right now.
It's an odd wish that Kama has for "some mourning." I though maybe the story was about having to rush through a loss and the poor girl never had a chance to mourn her father's death. So she wanted to know ahead of time if her brother was going to die so that she'd...
Oh. Yeah. That makes more sense. Some warning.
The two phrases are often identical. After some consonants it's common for a [w] to be deleted. As evidenced by the some warning/some mourning confusion the deletion can even occur across a word boundary. Between the labial [m] and rounded [ɔ] is an especially suitable environment for w-deletion. It can be hard to distinguish between some more and some wore (except that the former is usually an iamb and the latter is often a trochee). And we sometimes find this deletion after other consonants in words like towards [tɔrdz] and quarter [kɔɻɾɻ]. These words can still be pronounced either with or without the [w], while sword lost it permanently long ago (except in the not-so-common spelling pronunciation).
Of course there are several words in which the deletion does not occur. Before a front unrounded vowel the [w] stays put in tweed switch square and quack. If a speaker pronounces quartz with a distinctly low and unrounded [a] my guess is that the [w] is regularly preserved. I've never heard the mineral pronounced identically to carts.
I'm not prepared to give an answer to the question that I now pose: why did sword lose the [w] while swore has kept it? Usually we look to the original language or the time of adoption to help with an explanation. Because both words have been with the language since it was Old English that doesn't give us much help. It may have something to do with the preservation of a front vowel in swear. By analogy with a related form the [w] could have been preserved by kinship.
But that's only a primary suggestion and I'm happy to hear a more informed explanation.