Southernese.

Okay, today I had to explain to a Yank........I mean a Northerner, what the phrase Y'all All means.

Let me explain it to y'all.

Okay "Y'all" can be a plural or a singular noun and yes, you DO need the EXTRA "All" in there.

Example:

You have a group of people. You have two jobs. You direct them by dividing them into two groups.

Then, you tell them, motioning to the first group......"Okay, now Y'all start cutting the hay." Then you motion the the second group and say, "And Y'all start baling the hay." Then you motion to the entire group and say, "And Y'all All are stayin' for supper tonight!"
The first two are used as singular nouns referring to a group as a single entity. The last one is used as a plural noun referring to them all as a group.

Any questions?