There is, however, indirect
circumstantial evidence from other areas of science that may provide
an answer to these two questions. Both the archaeological record (in
terms of bones and artifacts) and human genes (in terms of gene frequencies
and mitochondrial DNA) indicate that all modern humans share a recent
common ancestry in Africa. What is surprising, and difficult to explain,
is that people who look just like us — modern humans — first
appear in the archaeological record one hundred thousand years ago.
But these people did not behave like us; they are indistinguishable
from Neanderthals in both their toolkit and their behavior. It was only
around fifty thousand years ago that — quite suddenly —
both toolkits and behavior started to change with amazing rapidity.
Toolkits that had remained unchanged over hundreds of thousands of years
began to change with the rapidity of tennis-shoe styles today. And styles
that had been uniform over huge geographical distances began to differentiate
in neighboring villages. People began to fashion tools from other materials.
Whereas previously only stone had been used, now bone, shells, ivory,
and other natural materials were employed. Art appeared for the first
time, burials became more complex, and people seem to have spread out
of Africa to inhabit the entire world, replacing earlier inhabitants
(Neanderthals) or occupying territories hitherto uninhabited, such as
Australia, Oceania, and the Americas.
Ruhlen talks about the
development of the fully modern language
and possible reasons for a sudden change in language
and human behavior.
We arrive at the final question in our story. What advantage could have allowed a small African population to leave Africa fairly recently and, in a short time, occupy the entire world and replace all previous human inhabitants? A growing number of scholars — linguists, archaeologists, and geneticists — believe that it was the appearance of fully modern human language around fifty thousand years ago that bestowed this enormous selective advantage on a small African population. If this scenario is correct, then the similarities among the world's extant languages not only support the idea of a recent African origin for all modern humans, they also explain it. The invention of modern human language fifty thousand years ago led to the explosive expansion of modern humans around the globe. And even today traces of this sudden expansion persist in languages around the world.
Persisting in languages around the world are traces of the sudden expansion of humans at the time of the development of the original fully modern language. Merritt Ruhlen discusses how these traces can be seen in certain widespread roots as a result of their common origins.
published Spring 1999.