Odd. I have a history book I can't lay my hands on right now (books in storage) which said there was a mining jargon for the Swahili, Xhosa, Sesotho and Swazi workers they all had to learn. It's called Fanakalo. Apparently its like a pidgin with a lot of Bantu.
But if you say they gave up and just used Africaans I can believe it.
But if you say they gave up and just used Africaans I can believe it.