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

cavemen weren't good abstract thinkers

Neanderthals were the superintelligent white master race until they were bred out of existence by the barbaric Homo Sapiens Sapiens.