Why It's Always Sunny (Mostly) Decided To Drop The Philadelphia Accent
The characters on "It's Always Sunny in Philadelphia" are all Philly natives who have lived in the city for their entire lives, but none of them really seem to speak with a Philadelphia accent. Only one cast member is actually from Philadelphia, and even he doesn't have much of an accent, so what gives? On the episode of the "Always Sunny Podcast" where Charlie Day, Rob McElhenney, and Glenn Howerton discussed "Mac and Charlie Write a Movie," the trio revealed why the characters don't speak with traditional Philly parlance other than the occasional slip from McElhenney, who grew up there. It turns out that the Philly accent is really unusual and not only would it be difficult for the actors to nail it, but audiences might not believe it's real.
If you ask a dozen Americans from around the country what a Philadelphia accent sounds like, you'd probably get a dozen very different responses, so the guys were probably onto something when they decided to tone down the accents as much as possible. It's hard to imagine the quick back-and-forth and yelling on the series with strong Philly accents on top ... they might have had to include subtitles for everyone not from the City of Brotherly Love.
Breaking down the Philly accent
There are only a scant handful of times when the series features Philadelphia accents. In "The World Series Defense," a couple of McElhenney's friends from his childhood in Philly play some rowdy Philadelphia Phillies fans who defend their mascot from an overeager Charlie (Day) dressed in his Green Man costume, and their accents are true Philadelphia, but other than that the accent is pretty scarce other than background characters.
In the podcast episode, the guys discussed what the Philadelphia accent sounds like. Day describes it as "Boston accent slammed with the deep south mixed with England," and then all three of them agree that there's some Australia mixed in as well. (Maybe that's why Howerton's character Dennis sounds like Crocodile Dundee when he's trying to do a Philly accent in "Chardee Macdennis 2: Electric Boogaloo...") Day explained to listeners why they decided not to do Philly accents rather plainly:
"Well you remember when we first started the show, when we were debating, do we do the accents or not? And we're like, people won't know what the f*** we're doing. They're gonna be like, 'What is this?'"
The solution was to choose just specific words to use the accent with, and sharp-eared fans can catch that unique twist on pronunciation every now and again. For example, both "birds" and "hoagie" have a Philly pronunciation, though whether that's intentional or not is known only by the gang.
A sort-of Philly accent
There's one actor that goes "in and out of" a Philly accent, according to the guys, and that's Danny DeVito, who plays Frank Reynolds. DeVito's pronunciation of various words has always been kind of unusual ("whore" becomes "hoor," for example), but the guys have noticed that it gets stronger and weaker from season to season. In the podcast, Day says that he noticed DeVito "ramped it up this year a little bit," bringing more of the Philly flavor than he had in previous years. That's the strongest it's been since the early seasons when he was first playing with the idea, which sounds like a good reason to do a season 16 re-watch.
My personal fan-theory is that DeVito's native New Jersey accent shares some similarities with the Philadelphia accent and that he slips into a stronger Jersey accent every now and again. New Jersey accents sound sort of like New York accents which sound sort of like Philly accents ... at least if you're not from there. Maybe in season 17 we'll get an episode where the entire cast speaks in their version of a strong Philadelphia accent. Stranger things have happened, and it could be really freakin' funny.