It will take years before the first men develops a language.
I assume our first parents use sign language.
They have no idea what words to use since they have no one to teach them.
If a child is born on a remote area where there is no people around.
He will never learn to use language. or utter a decent word.
So if Adam and Eve were the first parent.
They could never talk to the serpent who seduced them to sin.