The Philadelphia study

The Philadelphia study was a study designed to test the Curvilinear principle as referred to by William Labov, through careful gathering and analysis of research on language variants in five Philadelphia neighborhoods. His research goal was to "...discover the social location of the innovators of linguistic change and therefore focuses on the embedding of individuals in their neighborhood."

To test his hypothesis, Labov identified socially and ethnically central groups by gathering information on five Philadelphia neighborhoods through census data and initial surveys. He selected particular blocks in each neighborhood as an initial research point using a specific set of criteria including full occupancy of dwellings, high levels of interaction between people, and public spaces where interaction can occur. The field workers presented their research goals to the residents broadly and “without singling out language for specific attention” in the sociolinguistic interviews. The goals of these interviews were to gather social data on the residents, their block, and the neighborhood and analyze linguistic variants without facing the problem of the Observer's paradox. That is, the field workers attempted to create an environment where the speaker would speak informally.

To gauge each speaker’s social position within the community, Labov created a socioeconomic status index based on education and occupation, each ranked on levels from 0 to 6, where 6 was the highest level of education or occupation. He studied a series of “new and vigorous” vowel changes, including the fronting and raising of (aw) and (ey) and the centralization of (ey). He also studied the nearly completed changes involving (ow) and (aeh) and incipient changes such as the lowering of (e) and (ae).

Labov discovered that incipient changes did not provide a strong correlation with age or social class because these variants were too early in their stages of development to display any social significance. The nearly completed and most advanced changes displayed the most stability within the study and showed intermediate correlation with the middle classes. The new and vigorous changes—the focal point of the study—displayed the strongest curvilinearity and most clearly encompassed the linguistically innovative nature of the inner classes.

Through these Results, Labov asserted the truth and significance of what he named the Curvilinear Principle. With the social information gathered from the interviews, he discovered that it is not the education or occupation factors that drove the middle class to spur linguistic change. Rather, it was the central location within their communities—both socially and literally. They were not only central in the social hierarchy, but also in their local environments and interactions.

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