The North American Midland as a dialect area

by Sharon Ash
in Langauge Variation and Change in the American Midland

the Midland is a coherent dialect area, although there is considerable variation within it.

p. 55 :The Midland is a dialect region, positively defined by a variety of phonological, lexical, and syntactic features."
p.56 "...it is set apart by a anumber opf defining features, even while individual cities have their own unique character."