What language cavemen could program in?

C/C++ syntax is quite unforgiving for mistakes, and cavemen weren't good abstract thinkers.
I think something like a variant of LISP or Forth could be used to teach a cavemen basic programming.
Haskell or restricted subset of it, would look like pseudocode and could be more palatable to primitive cavemen

>>6
Is "primitive members of the Homo sapiens species that would often dwell in caves" better?