Nocy is locative after w, correct? I know w gets an accusative in some cases, but the accusative of noc is just noc. So is it correct that it's locative?
An Accusative usage would be for example "W tę noc napadniemy na bank" = "(In) This night we will rob the bank"
So, does the i after c cause it to be pronounced a bit like a ch in English, but the y does not? Is it, essentially an extreme palatalization?
Yes, i after c causes it to be pronounced exactly like the Polish letter ć, i.e. a bit like a ch in English but with your tongue in the same position as if you were saying the y in yes (palatalization).
The letter y does not change the pronunciation of the letter c, so it’s still pronounced like ts in let’s go.
In the example, I do not hear the "w". Does it "get swallowed up," as it were?
I find those short single letter words usually get pronounced like they are part of the next word. So it probably sounds like "Śpimy wnocy"
it seems that we are lucky to be able to slow down the audio, otherwise one cannot hear the "w" being said. I see that there were a few comments a year ago, still the same. No wonder I have to ask my Polish friends to speak slowly!