Back to hottentot...
So in Dutch, it's known to mean stammer (and German hotteren-totteren = stutter according to askoxford), but it's not considered offensive.
Is it really possible to refer to group as "those people with a speech impediment" without thinking it might be just a tiny bit, oh, insensitive?
It seems to me that wishing on piebald horses would be a successful business there. (^_^)
(In case that doesn't "translate": If you make a wish on a piebald (spotted) horse without thinking about its tail, the wish will come true.)