Words are inadequate

I'd always thought that /everyone/ pronounced it with four, and that people who used five were just being overly literal to be funny, like pronouncing "February" like it's spelt. Then a couple of months ago a friend of mine mentioned how she'd spent some time in "lew-eez-ee-an-uh" and I did a double-take. Since then I've been sort of obsessive about asking new people where they're from and how they pronounce it.

There's a weak correlation between 'raised southern' and 'four syllables,' in that not all southerners use four, but everyone who uses four was raised southern. (I learned to talk from two Arkansans, so I count myself as 'raised southern' here.)

As to your actual question :) I think it's a distinction between 'south Louisiana' (Creole country) and 'the rest of the South.' NC and VA and KY, and even TN, are weird in that regard, they've had some linguistic drift towards Yankee speech patterns. (Just don't tell them that.)