The reduced short-a system common t

The reduced short-a system common to African American and Hispanic speakers in the lower left corner of Figure 10, with a single /æ/ category, can be viewed in two ways. It may represent the transmission of a prior pattern independent of the traditional Philadelphia system or the result of a gradual diffusion from the Philadelphia system that progressively loses detail. The second possibility aligns the Philadelphia development with the proposed explanation for the origin of the general raising of short-a in the Northern Cities Shift of western New York, as a simplification of the many disparate short-a systems that were brought into contact in the building of the Erie Canal (Labov et al., 2006:216). This calls up a somewhat paradoxical generalization: Faithful transmission preserves the irregularities of a system produced by lexical diffusion, but less faithful diffusion can reduce those irregularities to a more regular phonological pattern. This indeed is what seems to have happened in the diffusion of the New York City short-a system to other regions in the 19th century (Dinkin, 2009; Labov, 2007).



C ONCLU SION

The study of large urban speech communities began with a focus on linguistic differentiation, but as the regularity of social stratification emerged, it gradually became apparent that these cities were united by common patterns of style shifting, reflecting a common set of norms. It also appeared that there was a common structural base for that shifting, with a common definition of the linguistic variables involved. To a surprising extent, these great cities turned out to be geographically uniform, and the local designations such as “Brooklynese” or “South Philadelphia” were actually labels for social class patterns of speech. But that uniformity stops short at racial lines, where we find abrupt discontinuities between Black and White.
Given the fundamentally outward orientation of the language learner (Labov,
2012), the forces that create such deep divisions in the speech community must


indeed be powerful. As we have seen, the major factor that is operating here is the amount of communication across racial lines. African Americans in this city are Philadelphian in many ways. They eat cheese steaks and hoagies, call out “Yo,” and walk on the pavement. Some linguistic features spread easily across the racial lines, in both directions. But the more abstract features do not make this transition. When Whites attempt to mimic African American habitual be, they just get it wrong, saying things like “This be Saturday.” Unless they grew up with black friends, they fail to notice the habitual meaning associated with the invariant form. African Americans who do not come into intimate contacts with Whites until the critical period is past will not even approximate the Philadelphia short-a system. Words and sounds may diffuse from one community to another, but systems do not.