NCVS meaning in Regional ?

Inland Northern (American) English, also known in American linguistics as the Inland North or Great Lakes dialect, is an American English dialect spoken primarily by White Americans in a geographic band reaching from the major urban areas of Upstate New York westward along the Erie Canal and through much of the U.S. Great Lakes region, as far west as eastern Iowa and certain demographics in the Twin Cities, Minnesota. The most distinctive Inland Northern accents are spoken in Chicago, Milwaukee, Detroit, Cleveland, Buffalo, Rochester, and Syracuse. Features of the Inland Northern accent have also infiltrated a geographic corridor from Chicago southwest along historic Route 66 into St. Louis, Missouri; today, the corridor shows a mixture of both Inland North and Midland American accents. Linguists often characterize the western Great Lakes region's dialect separately as North-Central American English.

The early 20th-century accent of the Inland North was the basis for the term "General American", though the regional accent has since altered, due to the Northern Cities Vowel Shift: its now-defining chain shift of vowels that began in the 1930s or possibly earlier. A 1969 study first formally showed lower-middle-class women leading the regional population in the first two stages (raising of the TRAP vowel and fronting of the LOT/PALM vowel) of this shift, documented since the 1970s as comprising five distinct stages. Evidence in the mid-2010s has suggested a reversal of some features of the Northern Cities Shift in certain locations.