"It may seem surprising, but in this age where geographic mobility and instant communication have increased our exposure to people outside of our neighborhoods or towns, American regional dialects are pulling further apart from each other, rather than moving closer together. And renowned linguist William Labov thinks there’s a connection between political and linguistic segregation.
"Labov suggests that it’s these deep-seated political disagreements that create an invisible borderline barring the encroachment of Northern Cities Vowels. When he looked at the relationship between voting patterns by county over the last three Presidential elections and the degree to which speakers in these counties shifted their vowels, he found a tight correlation between the two. And the states that have participated in the vowel shift have also tended to resist implementing the death penalty.
"Social identities are complex, and can be defined along a number of different dimensions like class, race, or ethnicity. Not everyone feels that politics are a part of their core identity. But I suspect that political ideology may become an anchor for accents to the extent that large social groups collectively identify themselves by their political beliefs. According to Bill Bishop, author of The Big Sort, this is happening more and more as Americans voluntarily cluster themselves into homogenous, politically like-minded communities."
Via Seth Dixon