As always, it’s impossible to follow up the amazing posts of CBH, but here I go.
I’m guessing Rocky is carrying on Crankshaft’s illiteracy? Because I don’t know why Cory is reading that sign out loud if she can read it for herself. It’s also weird because it’s easily legible for anyone reading the strip, so there’s nothing at all added by him reading it. Of course the joke is “Cory’s mom is excited for him to get married” which I don’t think is a joke or really worth spending a day of a strip on, but that’s Batiuk for you.