Why do New Orleans people say 'where y’at?'

This 1975 photo of Irish Channel resident Red Jack II, enjoying a Budweiser, was taken during that year's Irish Channel St.”  may have come to both the Atlantic Coast of Canada and the port of New Orleans with Irish immigrants.Patrick's Day parade.Nathalie Dajko, a Tulane University associate professor of linguistics, believes the phrase “Where y’ at?