Speech and language skills are unique to modern humans. While this ability evolved over millions of years, it is not possible to trace language in the fossil record because it leaves no direct imprint. Instead, re-examining the ways our nearest living relatives communicate is helping to unravel this mysterious capability.
The mystery is deepened by the fact that our closest living relatives, the great apes, do not talk. Some scientists now believe that the evolution of our language capabilities are more discernible in living primates than previously assumed.