Interesting 1976 map of English dialects in Texas, demonstrating the divide between the more Deep Southern accent of East Texas (drawl) vs. the more Appalachian accent of North and West Texas (twang)
In the USA, why is the (steretypical) southern accent often referred to as a 'country accent'? Is this misleading or is it a fair label? - Quora
Rhoticity in English - Wikipedia
What are some common examples of regional dialects in the United States? - Quora
Dialects
What's the origin of Texas accent? - Quora
Map of North American English Dialects, Based on Pronunciation
Why are southern accents spoken by only the poor and rural now (mostly), instead of all the middle class and rich when everyone in the south used to have southern accents?
Cultural Geography Archives - Page 3 of 26 - GeoCurrents
View the meeting handbook - Linguistic Society of America
American Dialects : Dialect map of American English