What is the original language of Africa?
If there was an "original" language for the entire continent of Africa, it is unknown. For all of known history, Africa has had thousands of languages.
Africa is a continent. It therefore does not have one specific original language.
Is Afrikaans is a mixture of English words and words learned from Black Africans and other settlers?
The Zulu have lived in Africa for many thousands of years. It is believed they arrived in southern Africa about two thousand years ago. Today, the Zulu are the largest ethnic group in South Africa, numbering close to twelve million people. Their language is Zulu, part of the Bantu language group, and is an official language of, and the most widely spoken language in, South Africa today.