He was a phonologist and sociolinguist, specializing in the field of African languages. He taught at the State University of New York (State University of New York), Binghamton, for 22 years. He was chair of the Anthropology Department from 1996 to 2001.
Foreign some years in the 1990s, Bob was professor and head of the Department of African Languages at the University of the Witwatersrand, in Johannesburg, South Africa.
He was subsequently provost and vice-president for academic affairs at Youngstown State University, Ohio. His academic work extended to an important hypothesis on the genesis and transmission of "isihlonipho sabafazi", that is, the complex system of linguistic avoidance traditionally acquired by married Xhosa women (also called the Xhosa women"s "language of respect").