Philadelphia English is a variety or dialect of American English native to Philadelphia and extending into Philadelphia's suburbs in the Delaware Valley. The geographical extent includes nearby Reading, northern Delaware centered around Wilmington, South Jersey centered around the Atlantic City and Hammonton metropolitan area, and much of Central Jersey. The Philadelphia accent, which has vigorously been in a complicated state of flux since the twentieth century onwards, is one of the best-studied in American English, as Philadelphia's University of Pennsylvania is the home institution of pioneering sociolinguist William Labov. The mid-twentieth century Philadelphia accent is very similar to the Baltimore accent; in fact, the local varieties of the two cities together constitute what Labov