In the Ghanaian language, according to the Associated Press, Nana means "King" and Kwadjo (pronounced "Kwo-Jo") means "boy born on Monday" (April 10 was, indeed, a Monday).
In 1992, Hayes, 63, was crowned honorary king of Ghana's Ada region in honor of his humanitarian work.
He and Adjowa were married in May 2005.
In January, news sources reported that the Memphis-based Hayes suffered a mild stroke. At the time, friends said the stroke was brought on by exhaustion.
Since 1997, Hayes, best known for his hit song "Theme from Shaft," had voiced the role of South Park's school-cafeteria sage, Chef.
This season, he abruptly quit over what he called the show's disrespect for religion. South Park creators Trey Parker and Matt Stone speculated that Hayes was offended by the show's treatment of his faith, Scientology.