True story: A North Carolina teacher gave an example to his class of a statement by the school's football coach: "I'll be done drove there by 3 o'clock." Now, the teacher said, give the correct future perfect tense of that sentence. A boy's hand shot up. "I'll be done drive," he said proudly.

Borne out in grammatical and metaphorical mazes, talkin' Southern – or talkin' country – is the cadence of Atticus Finch and Andy Griffith, presidents and preachers, ballplayers and businessmen in Brooks Brothers suits. To many Americans, it's also the lingua franca of honky-tonk pluckers, bumpkins, rascals, and hicks.

Yet in an urbanized America drawn ever closer by high speed communications and swirling migrations, a quiet debate is now surfacing among linguists – in all kinds of English – about whether Southern talk is spreading or becoming as quaintly provincial as a coon hunt.

Some believe that the Southern drawl has expanded to the point where, arguably, more than half of all Americans now glide their diphthongs and hush their R's like modern-day Rhett Butlers. Some professionals who travel around even adopt different regional dialects as they go, knowing it's one of the best ways to get ahead.

But other experts believe mass communications and urbanization are cutting away at the distinctiveness of the Southern voice, resulting in a more mono-pitch America.

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John Fought is in the expanding camp. The linguist from Diamond Bar, Calif., points to several factors leading to the growing use of "y'all," "fixin' to," and other dialectical Dixie quirks: the migration of Northerners to the South, the link between notions of masculinity and language, the appeal of country roots, and the influence of cultural phenomena like NASCAR.

"The boundary for Southern speech actually has spread," says Mr. Fought. "And we're seeing fairly large fingers and puddles of more or less Southern speech north of the Ohio River and West of the Mississippi into the Plains."

Other linguists aren't so sure, noting that locale doesn't always dictate dialect. Indeed, Erik Thomas, a vowel expert at North Carolina State University (NCSU) in Raleigh, says research shows that mainstream English, otherwise known as American Standard, is actually nibbling away at both the borders and the urban core of the South.

In the North, new words, slang, and speech patterns tend to hopscotch from city to city and then spread into rural areas. In the South, that phenomenon is reversed: Speech patterns tend to trickle from the country to the city. Signs today, however, suggest that the drawl is coming up against a wall in expatriate hot spots like Atlanta; Birmingham, Ala.; and Charlotte, N.C.

"Northerners still make fun of Southern speech," says Dennis Preston, a linguist at Michigan State University in East Lansing. "To them, it stirs up images of sitting out in a cabin, polishing a gun, and scratching a hound dog." With that in mind, he adds, "Southern speech is certainly not spreading. It's enormously resisted in the South by those who would give them the biggest numbers" – newcomers from the North.

In many ways, the argument over the pervasiveness of Southern-speak centers on whether to count African-American vernacular as part of it (most experts do) and what to do about the pockets of Southern talkers north of the Ohio River. Ypsilanti, Mich., for instance, is sometimes called Ypsitucky because of all the Kentucky expats.

An additional problem is how to define Southern-speak. The classic drawl, though native mostly to Daughters of the Confederacy, is somewhat of a misnomer. In fact, pronunciation, syllable beats, and vocabulary define Southern speech more than speed. It turns out that the average Southerner, research shows, gets to the end of a sentence just as fast as a New Hampshirite.

One wild card in the argument over the spread of Southern talk is the "bidialectical" – a breed of people of unknown numbers who speak different dialects, often depending on who they're with. Are they evidence of "y'all" creep or just poseurs? Mr. Preston is one of them, quickly switching from his Kentucky hill country twang to what he calls "midlands speech" at Michigan State when he crosses the Ohio. He still, however, says "pin" for "pen" no matter where he eats his grapefruit or grits.

To speak "true Southern," a person has to be able to master several things, according to linguists Guy Bailey (chancellor of the University of Missouri-Kansas City) and Jan Tillery. These include everything from vocabulary (such as "snap bean" and "redbug") to upgliding diphthongs ("dawg" for "dog") to dropping the "R" in words ("foty" for "forty").

"These changes are both idiosyncratic and social," says Preston. "There seem to be personal characteristics that allow the dialect shift, including gregariousness and the ability to do it."

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Interestingly, mobile professionals switch between accents more often than other groups, apparently believing that success is dependent on dialect. Moreover, the mastery of language is deeply personal and even gender-biased. When a couple moves south, for example, it's much more likely that the man will acquire Southern speech than the woman. Conversely, when a Southern couple moves north, the woman is more likely to adapt her accent.

Some researchers, at least those from the South, believe that this has to do with the masculinity associated with country talk. Some Southern men grow up thinking that Northern dialects are for "sissies."

But often it's the capability of, and interest in, verbal dexterity that really accounts for bidialecticals. "There are people who ... could take a car trip to Texas from Minnesota without picking up anything," says Fought. "Other people can't help it. They just soak it up as they pass by."

Thomas Wikle, a geography professor at Oklahoma State University in Stillwater, has a father-in-law in Athens, Ga., who is aware of his accent around the local college campus, but falls into an almost incomprehensible brogue when talking to his farmer buddies out his truck window. That self-conscious instinct to suppress country talk in respectable company is a testament to the power of dialects, and that accent can, and often does, account for social status.

Unlike bilinguals, bidialectals tend not to brag about their abilities. "If I'm around my friends in Oklahoma, I don't even think about saying 'y'all,' but when I go back home to California and it slips out, someone usually gives me a funny look," says Mr. Wikle.

Today, the historic separation between North and South is less important than rural and urban differences. The debate over the use of Southern speech, at the very least, shows the importance of how people talk when they're at home.

"You get into identity features, which are really crucial in determining whether someone retains or loses an accent," says Mr. Thomas at NCSU. "That's why in rural areas of the South, Southern features are still pretty strong. All this identity with Southernness – what type of music you listen to, the sports you watch on TV, what kind of food you eat – it's prestigious to you and your friends to identify with sounding country."