In this chapter I discussed the surface phonological structure of Chicago White English and presented a number of results of a large-scale acoustic analysis of vowels in the speech of three speakers of the Chicago white vernacular. All vowels occurring in lengthy, continuous sections of tape-recorded sociolinguistic interviews were examined, measuring all occurring acoustic vowels. Vowel quality as measured by formant frequencies at vowel nuclei was shown to reflect the progress of the Northern Cities Chain Shift, which is shifting the low vowels and the short mid vowels in this dialect in a circle. The acoustic effects of phrasal stress were also shown to follow a clear and rather precise pattern, of phonetic shift of the nucleus of vowels in the direction of a high-central reduction target, which appears to be different from the target that Jamaican short vowels shift towards. These patterns are part of the system of phonetic implementation by which abstract phonological categories, quite closely related to those of Reference American, are realized by patterns of phonetic form which are characteristic of the vernacular dialect spoken in Chicago.