Map of the northern cities vowel shift. Three isoglosses identifying the NCVS. In the brown areas /ʌ/ is more retracted than /ɑ/. The blue line encloses areas in which /ɛ/ is backed. The red line encloses areas in which /æ/ is diphthongized to [eə] even before oral consonants. The areas enclosed by all three lines may be considered the "core" of the NCVS; it is most consistently present in Syracuse, Rochester, Detroit, and Chicago.
Own work; base map is modified from Image:Map of USA with state names.svg; data from W. Labov, S. Ash &amp; C. Boberg, The Atlas of North American English (Mouton de Gruyter, 2006), p. 204.
Angr