Sometime around the 1960s and '70s, people in Philadelphia began slowly, subtly to change how they speak. The sound of their vowels started a gradual shift consciously imperceptible to the very people who were driving it. A's evolved to bump into E's. The sound of an O lost some of its singsong twang. After decades of speaking with what was in effect a southern dialect, Philadelphians were becoming – linguistically, that is – more northern.
"There's one big question: How is it possible that Philadelphians all over the city are doing the same thing?" asks Bill Labov, a professor in the department of linguistics at the University of Pennsylvania. "What is it that makes Philadelphia operate as a whole, making it different from the neighboring cities?"
We often talk about regional dialects as if they were disappearing in the face of national TV. But, in fact, while classic southern patterns of speech have been receding in large urban centers in the south, northern dialects have continued to grow stronger. And these trends are best observed in large cities, or, more specifically, in neighborhoods like South Philadelphia where densely clustered row houses can mean that language change moves as quickly between neighbors as gossip.
"The idea is that in large urban centers, the density and intensity of social interaction is such that it's really a hotbed for linguistic innovation," says Josef Fruehwald, a Ph.D. candidate who's been working with Labov. "Despite the broad idea that mass media is what's spreading language change – that we're all becoming more similar – what really matters is face-to-face interaction with peers."
(This does, by the way, also mean that suburbs are decidedly not hotbeds of linguistic innovation. "If your house is set back 40 feet," Labov says, "you'd need a pretty good excuse to come say hello to your neighbor.")
Labov began studying the speech patterns of Philadelphians in the early 1970s with his students. Looking back over all the data and audio collected since then from hundreds of speakers in dozens of neighborhoods – all of it more recently parsed with automated acoustic analysis – Labov, Fruehwald and Ingrid Rosenfelder have documented a city changing its linguistic identity. Their paper, "One Hundred Years of Sound Change in Philadelphia," recently published in the journal Language, methodically tracks the speech of residents in the city born between 1888 and 1991.
All of the recordings come from locals who Fruehwald calls "dyed-in-the-wool Philadelphians," people who have lived in the city their whole lives, many of whose parents did the same. For most of us, dialect is cemented in the late teens. This means that people are time capsules of the way language was spoken when they were that age. And so an audio recording of an 80-year-old Philadelphia native captured in 1975 can give a sense of how most people in the city spoke circa 1915.
So what does the evolving sound of Philadelphia sound like? Language change, particularly in America, is observed over time in the way we pronounce 16 different vowel sounds. Here, Fruehwald explains what's happened to Philly's twang-y "ow" – as in down:
And the evolution of the sound "oh," as in "phone":
In each of those examples, Philadelphians have gradually abandoned over the last 50 years ways of speaking that we commonly associate with the South. At the same time, the pronunciation of words like "eight" has shifted to be much closer to "eat":
In this last example – in the pronunciation of the vowel sound in words like "ride" – another local pattern also becomes distinctively more northern.
"All of these changes are slight differences from generation to generation in how speakers are articulating these sounds, positioning their tongues in their mouth," Fruehwald says. "The acoustic measurement we're getting is reconstructing more or less how speakers' tongues were positioned in their mouths while they were speaking."
In all of these patterns since the 1970s (meaning among people born in the city roughly after World War II), the one common denominator is that the Philadelphia dialect appears to be realigning with its northern neighbors. Language evolves through relationships between people, but the changing sound of the city also has much to do with Philadelphia's relationship to broader parts of the country.
So what exactly happened in the period after World War II that sparked this realignment? There was no massive influx of people from the city's northern neighbors then. There was no dramatic population change. We do know, though, that as Southern dialects have been retreating in general, they have also become among the most stigmatized.
"The big question of why language changes lies beyond everything we do," Labov says. "So we attack it by breaking it down into small steps." They've already learned that women in Philadelphia (and in other communities) are the leaders of language change. And now they know exactly what that change sounds like and where it's going. The ultimate question, though, is what this evolution reveals about about how people relate to and communicate with their neighbors, be it next door, across town, or even farther away.
"I always tell my students, 'if you're only interested in the vowels, forget it," Labov says. "That's not what we want. We want to understand the neighborhood."