Y’all, which originates in the U.S. South, is a contraction of you and all. Although the word is generally considered out of place in formal writing, it can be useful when quoting speech or when seeking to affect a casual tone. If you do have use for it, make sure the apostrophe comes after the y. Ya’ll is a common misspelling.
Examples
On the web, y’all most often appears (outside social networking and comment boards) in breezy culture and commentary blogs—for example:
Anyway, apologies for the preamble, but since I’m filling in here for one week only, I wanted y’all to know where my head is at, Raising Hope-wise. [AV Club]
It’s the final episode of Gods of the Arena, y’all! [Houston Chronicle Tubular blog]
I am sure y’all were breathlessly awaiting the election results out of Estonia this weekend. [Dallas Morning News blog]
When quoting speech, don’t be afraid to use y’all when that’s what the speaker says. There’s no need to turn it into you all.

