Those humans who could talk were able to cooperate, share information, make better tools, impress mates, or warn others of danger, which led them to have more offspring who were also more predisposed to communicate (Poe, 2011).
This is a clear example of an evolutionary trait. Since being able to communicate lead to a better chance of survival and impressing mates the ability to talk was passed down quick. Those who could not talk weren't able to reproduce as fast. That explains the "Talking Culture" that the author refers to later.