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

>>1
Cavemen don't have developed natural language, so they require language to be symbolic, which leaves only Lisp. Although you would have to replace CAR/CDR with some more appropriate graphemes.