[I]n the 1760s, the Acadians, or Cajuns, arrived from Canada speaking a variety of French quite unlike Parisian French. In 1803, English-speaking settlers began to arrive in significant numbers, and throughout the 19th century the city saw heavy immigration from Germany, Ireland, and Italy. As the major port city in the South, New Orleans was also a gateway for the slave states, which brought in speakers of a variety of African languages. The slave trade also brought New Orleanians into contact with speakers of Plantation Southern English from the East Coast. And Midland English reached the city through river traffic headed down the Ohio and into the Mississippi River.
The language of New Orleans reflects this hodgepodge. There is substantial borrowing from French in banquette for "sidewalk" (now old-fashioned) and gallery for "porch," not to mention a large number of food terms including beignet, étouffée, jambalaya, praline, and filé. French-derived idioms include make the groceries for "to buy groceries; to shop for food" and make ménage for "to clean the house," both from the French faire; for, meaning "at (a specified time)" ("the parade's for 7:00"), is from French pour. A lagniappe, "a small gratuity or gift; an extra" is from Louisiana French but borrowed from Spanish, which itself took it from Quechua, an Indian language of South America. Similarly, bayou is from French but ultimately from Choctaw, and pirogue, a dug-out canoe or open boat used in the bayous, went from the Caribbean-Indian language Carib to Spanish to French to English. Gumbo is from French but ultimately from a West African language. New Orleanians also use many Northernisms, including chiggers for the biting mites that nearby Southerners usually call red bugs, and wishbone for the chicken part more usually known as the pully-bone in the South.
Alas, too busy to do anything terribly original today. But here is an excerpt from a Slate piece on New Orleans idioms that fits my recent posts on dialects and slangs: