Most commonly heard in the Southern United States, though growingly in other parts of the U.S. because of use in social media and television. Often y’all is seen as a marker of low intelligence or bad education, likely due to a lingering anti-Southern bias from the post-bellum period. Y’all is a highly useful word, a plural form of the second person pronoun (you). This function is important because, unlike every other standard pronoun, you does not have a separate plural form. Y’all is one of many plural forms for you used in certain English dialects. The chart below shows the state of English pronouns each with a clearly distinguished standard form, except for you.
You: You [Y’all, yez, yous, you-uns, yinz]
He, She; They
At one time there were four words all meaning ‘you’ in the English language. Thou and thee were the singular subject and object pronouns; ye and you were the plural subject and object pronouns. However, these four moved down to one leaving a space where a distinct plural form should be. Y’all neatly fills that space and has even began to have other forms such as y’all’s as in “y’all’s car.”
Kellerman, S., O’Conner, P. T. (2012). Yinz, you-uns, you-all, and company, The Grammarphobia Blog. Retrieved from http://www.grammarphobia.com/blog/2011/02/yinz.html.