Traditional dialect boundaries in the United States have received renewed attention (Labov, 1991, 1994). Labov outlined three dialects of English (the Northern Cities Chain Shift, the Southern Chain Shift, and the Third Dialect), the boundaries of which are defined by chain shifts in the vowel system and roughly correspond to traditional dialectal boundaries defined through the bundling of lexical items (Kurath, 1949) and phonological isoglosses (Kurath & McDavid, 1961). Other research has suggested that the Third Dialect may be the most heterogeneous of these dialects, with speakers in different areas displaying widely disparate behaviors (see, e.g., Clarke, Elms, & Youssef, 1995; Di Paolo, 1988; Di Paolo & Faber, 1990; Labov, 1996; Moonwomon, 1987). The present article contributes towards a richer picture of the Third Dialect by offering the first systematic variationist analysis of speech in Pittsburgh, with a particular focus on three phonological processes: vocalization of /l/, laxing of /i/ before /l/, and laxing of /u/ before /l/. I argue that Veatch's (1991) model of English syllable structure provides a unified account of these seemingly unrelated phonological changes in Pittsburgh; the implications of this argument for further research on Pittsburgh speech are also noted.