Why did many African Americans want to move away from using this specific dialect in works of literature?

In the 1960s, the South was a place African Americans fled, seeking better jobs and better lives in the North in what was known as the Great Migration. But in recent years that flow has switched and led to what’s become known as the Great Reverse Migration, with large numbers of African-Americans moving South again.

Explanation:

this isnt an english question.