On the hot, humid streets of New Orleans, Louisiana, it's easy to pick out the locals with just one word: "'Nawlins". That's the name of their fair city, pronounced in the proper Bayou drawl. Far to the north, but equally striking to a visitor's ear, Boston natives can be heard ordering "clam chowdah" or giving someone directions to "Hahvad Yahd."

So what causes these distinctly different dialects?

"There are a number of reasons that dialect changes throughout America," says James Lantolf, Penn State professor of Spanish and linguistics and director of the Center for Language Acquisition. "First of all, the patterns of settlement when the area was first discovered and developed have a huge impact."

James Collins

For instance, Lantolf points out, the regional dialect of New Orleans is largely attributable to the many different nationalities that developed the area. French, Irish, African American, Creole, Spanish and other European influences can all be heard within the Crescent City version of American English.

"A region's geographic location also has a direct influence on the development of a local tongue," Lantolf says. "Isolated areas, such as New Orleans, develop different dialects," he explains. "Where there is no contact between regions, entire words, languages and vernaculars can grow and evolve independently.

"Social standing and education also affect the vernacular of an individual person—and that extends to a particular area as well," Lantolf notes. "There is certainly a difference in the speech of the lower, middle and upper classes."

Lantolf points out that much of Pennsylvanian dialect "is a reflection of the influence of English and Irish settlers. Scranton has a particularly heavy Irish influence.

The pioneer settlers in Pennsylvania's anthracite region (which encompasses Scranton, Wilkes-Barre, Hazleton, and surrounding towns) were largely Irish and German Catholics who worked in the area's coal mines. Many Europeans—particularly Slavic and Italian immigrants—followed and contributed to the distinctive Coal Region culture and dialect.

The English spoken by their descendants is colored by their mother tongues: The word brogue itself (to describe an Irish accent) originally meant a "stout coarse shoe worn formerly in Ireland and the Scottish Highlands," and insultingly implied that the Irish spoke English so poorly, it sounded like they had a boot in their mouths.

The impact of Italian is heard in the regional tendency to elongate words—turning Acme supermarket into "Ack-a-me. And when locals replace the "th" sound in words with a "t" sound—"three" becoming "tree" or "cathedral" becoming "cateedral"—you're hearing the influence of Polish and other Slavic languages.

Pennsylvania's urban centers such as Pittsburgh and Philadelphia have their own vernacular. The word "yunz"—a kind of Northern "y'all,"—is quintessential Pittsburghese, whereas Philadelphians favor "yiz" to mean the same thing, a plural of "you" that doesn't exist in standard English. "These might seem like local slips of the tongue, but really they are the aspects of language that make dialects unique regionally." Lantolf says.

"It's interesting," he muses. "We call America the 'melting pot' because it eliminates the differences between individuals. But language—and its development—retaliates against that concept. Regional dialect separates people, to an extent. One region speaks this way, another region speaks that way; and the differences between the cultures that have influenced those regions become obvious in the language alone."

James Lantolf, Ph.D., is professor of Spanish and linguistics and director of the Center for Language Acquisition. He can be reached at jpl7@psu.edu.