I am looking for a children's mystery novel set in South Africa, of which I remember several details. I should say up front that the novel I am looking for is not Phyllis Whitney's "Secret of the Tiger's Eye", despite some similarities.
I remember the following details. (It is possible that I've conflated details from multiple novels here, but I'm pretty sure these are all from one book):
- The heroes are (I think) three children, all siblings, who are not South African natives. The oldest child is the protagonist. They are English speaking and I believe they are white.
- When the children are preparing for their journey to South Africa, they learn about apartheid and are taught to pronounce it as "apart-hate", which the protagonist agrees is an appropriate sounding word.
- One of the children receives a spelling lesson in which he is taught to remember that "there is 'a rat' in 'separate'".
- The youngest child pronounces "dungarees" as "doug-maries".
- There is an adult character, a South African native, who serves as the family's guide to South Africa. He is called Jojo.
- I'd have read this book probably in the early 1960s.
I seem also to remember that there is a very frightening scene in a cave, but that might be a false memory based on the cave scene in "Secret of the Tiger's Eye".
Googling doesn't seem to help at all with this. I'll be glad if anyone here can help.