http://www.newsweek.com/scientists-discover-evolution-speech-1854505

Why do we talk the way we do? It might trace back to when our ancient ancestors left the jungle for the open savanna.

Somewhere between 5.3 million and 16 million years ago, Africa's landscapes transformed from thick, leafy forests to wide-open grasslands. This environmental shift forced our ancestors out of the trees and onto the ground. Along with all of the physical and behavioral changes this may have caused, researchers also believe it may have changed the way we speak for good.