Since the 1960s, Wolfram has authored or co-authored more than 20 books and more than 300 articles on variation in American English. He was an active participant in the 1996 debate surrounding the Oakland Ebonics controversy, supporting the legitimacy of African American English as a systematic language system. In addition to African American English, Wolfram has written extensively about Appalachian English, Puerto Rican English, Lumbee English, and many other dialects of North Carolina, particularly those of rural, isolated communities such as Ocracoke Island.