So I've been watching breaking bad. A really interesting dialectical feature of the character Jesse, is his use of the word "yo".

At first I thought nothing of it, it's just "slang" or whatever; nothing to see here... However, the more I think about it, the more the actual semantics of it seem quite interesting.

The following uses are both relatively transparent:

He of course uses the meaning of yo that we're all most familiar with (as a greeting), as in:

"Yo! Anybody home?"

Also, at the beginning of a sentence, as a synonym of the exclamation "Hey!", as in:

“ It's like: ‘ Yo! Whatever happened to truth in advertising? ’ ”

This meaning, again, is easy to grasp.

However, it also comes up in a completely different way. Usually, but not always at the end of a sentence, as a sort of emphatic interjection.

For example:

"C'mon, yo!"

"I mean it, yo!"

"Let me tell you something yo."

"That is messed up yo..."

"Maybe this isn't such a good idea yo..."

In a way it reminds me of a tag question, or the way some dialects use "right" as in:

"So, I'm at the pub, right, and this guy comes up to me right, and I'm looking at him thinking, ‘ Who are you? ’. So anyway, right, I say to him..." etc.

But this isn't exactly it. "Yo!", does't work in the above example for "right". "right?", "know what I'm saying?", and other similar constructions are used to engage the listener, as an informal speech punctuator that essentially means "I want to verify you are engaged, and following what I'm saying.". Jessie's "Yo" carries a different meaning than that, and while I subjectively understand it when I hear it, it's difficult to pinpoint exactly what it is.

I can't think of another word or exclamation that fits in all the places where Jesse would say "Yo", and I can't seem to "crystallise" exactly what either the rules of its use, or what it exactly means. Is this use the same as (and borrowed from) its use in AAVE dialects, or is this something different?