Charles Albert Ferguson (July 6, 1921 – September 2, 1998) was a U.S. linguist who taught at Stanford University. He was one of the founders of sociolinguistics and is best known for his work on diglossia. The TOEFL test was created under his leadership at the Center for Applied Linguistics in Washington, DC. Ferguson was also the leader of a team of linguists in Ethiopia under the Ford Foundation's Survey of Language Use and Language Teaching. One of the many publications that came out of this was his article proposing the Ethiopian Language Area (Ferguson 1976), an article that has become widely cited and an important milestone in the study of contact linguistics.