and then there's always the plural plural for emphasis...... all y'all come back nao, ya heah?
That's one thing visitors to the south don't always understand.
Y'all is singular as in speaking to one person even though it is a contraction of "you all". A greeting to a single person is "How y'all doing today?".
When speaking to two or more people the plural form is used; "How are
all y'all doing today?"
The reason being, when you speak to an individual, especially wondering how they are doing, you are automatically including their family, hence
all of you. If any thing is going on, you are about to get an ear full; aches & pains, sister's gallbladder operation, grandma's trick knee, laid off work. etc...