Associated with U.S. southern dialect when addressing a group or more than a single person. However, increasingly used as an informal, softended singular pronoun well - "Y'all come back now." as opposed to - "Hey come back here!"

Also increasingly used as a gender neutral alternative to "guys" - Hey y'all, when are we gonna leave? Y'all wanna get some food?

Southern's way of saying "you are all" or "you all" without actually saying it.

When a southerner and a northerner 69 each other

How the fuck can y'all not understand what y'all means?

Contraction of 'you all' in some cases 'all you'. Used to refer to 2 or more people.

Texan for all of you

you all aka Southerners