OK, so since SNG suggested this (in the "Intelligent Design" thread), let's take a shot, eh?
Take a human baby, immediately from the womb; provide every physical need, but absolutely no direct contact whatsoever! No faces, no voices, no sounds, no other humans, no animals, no trees and leaves and flowers--just a pure and simple newborn, clean slate.
Would this baby naturally develop a language, some language, any language?
I submit that it would simply and fairly quickly die.
Craig