Back to New Orleans (where I've lived for 35 years -- not all my life, but more than half):

I *never* heard anyone pronounce it "N'awlins" before that erroneous phonetic spelling became popular about 15 years ago.

Here's how I believe that error developed:

Back in the early 1970's, the headline over an article by local writer John Newlin in the (now-defunct) Vieux Carre Courier used the spelling "No Awlins," which *is* a pretty good phonetic representation of the way most working-class locals say the city's name. It's three syllables (maybe two-an-a-half), NOT the two syllables convey by the neo-spelling "N'awlins."

I believe that some less linguistically sophisticated advertising copywriters bastardized "No Awlins" (which made sense, in the light of actual usage) and started the wide dissemination of "N'Awlins" (which never did represent anyone's actual speech pattern). Now, we have "local" TV personalities reading "Naw-lins" off cue cards and further popularizsing this mispronunciation.

Other ways to approximate an authentic phonetic spelling of the same or similar pronunciation might include "N'walins" "Noo-awlins," etc. The more genteel uptown community says it more like this: "Noo-wally-uns" (making "leans" into two syl;lables rather than one).

To confuse matters furhter: With or without contractions and other allowances for dialect, the accent should always be on the first syllable of "OR-leans" when used with the word "New," as the name of the city. However, when used *without* "New," as in Orleans Parish and Orleans Avenue, etc., the accent is properly on the second syllable ("Or-LEENZ"). Of course, there are many many songs incorrectly pronouncing the city name as "New Or-LEENZ," just because it scans and rhymes more easily.

We have many more pronunciation-related flukes around the city:
Burgundy Street is bur-GUN-dee, not BUR-gundy.
Chartres Street is "charters," not the proper French "shart[re]"
The nine streets named for the Greek muses all have quirky voicings:
Calliope is "cally-ope" not ca-lye-o-pee;
Melpomene is "MEL-puh-MEEN" (or even "mel-ka-meen") not mel-POM-any.
Then there's Burthe Street uptown, pronounced "Byooth."
Across the river in Algiers, Socrates St. is pronounced "so-crates" -- really!