Results of a 1975 sociolinguistic survey of all the ethnic groups of the South American Black population are presented. The sample of 3,653 people between the ages of 15 and 54 was from the urban and rural areas of all the provinces and homelands of the Republic of South Africa. Findings indicate that proficiency in English is relatively strongly focused on the reading and writing skills, whereas proficiency in Afrikaans, although approximately equal to that of English, is relatively strongly focused on the comprehension and oral skills. English is used more often than Afrikaans for reading and writing, whereas Afrikaans is used more often than English in communication with Whites at work. The popularity of English as the medium of instruction at school is much higher than Afrikaans, but Afrikaans, because of practical considerations, is not ignored by the Black people. These trends in favor of English are especially demonstrable among more highly qualified and also among the urban Blacks. Among the lower qualified and rural Blacks, Afrikaans plays an important role, especially in contact with Whites. It is suggested that English is more a language of prestige for the Black population, whereas Afrikaans has a more pragmatic value. Information is presented on the respondent characteristics of qualification level, geographic residence, age, and sex in order to better explain the state of English and Afrikaans among the various groups of Blacks. (SW)