Y’all arose as a contraction of you-all. It first appeared in the Southern United States in the early nineteenth century,[2] with an earliest citation of 1824.[4] Many aspects of the word's derivation are unknown; for example, no one knows if its use began with southern blacks or with white immigrants.[2] One supposition is that the term evolved from the earlier Ulster Scots term ye aw.[5] Scots-Irish immigrants to the Southern United States frequently used the term ye aw.[6] Some evidence suggests that y'all could have evolved from ye aw due to the influence of African slaves who may have adapted the Scots-Irish term.[7] An alternative theory is that y'all is a calque of Gullah and Caribbean creole una via earlier dialects of African-American English.[4] Y'all is an original form, deriving from indigenous processes of grammar and morphological change, not from input from other English dialects.[4]

Y'all appeared at different times in different dialects of English, including Southern American English and South African Indian English, and as such is a parallel independent development in those dialects.[8]

The forms ya'll and yall are also known, but the form y'all is the most prevalent in print, being ten times as common as ya'll.[9] Other less-common forms include yawl and yo-all.[2]