Complex sentence: American writers throughout the 20th century have used the dialect as the chosen speech of uneducated and unsophisticated characters, though research has largely disproven these stereotypes; however, use of the Appalachian dialect is still often an impediment to educational and social advancement.
Split into simpler sentences: American writers throughout the 20th century have used the dialect as the chosen speech of uneducated and unsophisticated characters. While research has largely disproven these stereotypes, use of the Appalachian dialect is still often an impediment to educational and social advancement.