You'd especially understand if you were raised in the south

Y'all'd've.

In this instance I'd probably use y'all'nt. But I only ever use my southern accent ironically or for dramatic effect.

I often get told I don't sound southern enough. XD

Yeah, from having grown up talking southern but listening to non-Southerners talk, I've figured out how to pretty much talk like I'm not from the South at all; but there's probably still some hint of Southern in there from just the way it formed in my brain at a young age XD

What's your word?

Wdym? Like which one would I use? Probably y'all aren't, or maybe ain't if I'm feeling jokey