Northern cities vowel shift
The Northern cities vowel shift is a chain shift in the sounds of some vowels. It is called northern cities because it has taken place mostly in a broad swath of the United States, beginning near Syracuse, New York and extending west through Cleveland, Ohio, Chicago, Illinois, and north to Minneapolis, Minnesota.
In this shift, the vowels in the words stuck, stalk, stock, and stack have shifted from IPA [ʌ], [ɔ], [ɑ], [æ] to [ɔ], [ɑ], [a], [eæ] (SAMPA [V], [O], [A], [{] to [O], [A], [a], [e{]).
