As the people spread out from Babel, they would have most likely gone off to settle, hunt, and build new communities in small family groups that understood each other’s language.
This would have caused different people groups that “were probably relatively isolated, very small and, as a consequence, fairly inbred," (LiveScience, 03/18/2013).
Although the Scriptures stand-alone without external proof, there is circumstancal evidence “The evidence comes from fragments of an approximately 100,000-year-old human skull unearthed at a site called Xujiayao, located in the Nihewan Basin of northern China. The skull's owner appears to have had a now-rare congenital deformity that probably arose through inbreeding, researchers report today (March 18) in the journal PLOS ONE. The fossil, now dubbed Xujiayao 11, is just one of many examples of ancient human remains that display rare or unknown congenital abnormalities, according to the researchers.” (ibid.)
Although the 100,000 year date is a part of the normal usual unscientific guesswork that is based on evolutionary assumptions, the evidence that humans were inbred, living small isolated populations, does lend itself to the Biblical record.
As the people spread further apart, dominant genes would have become more pronounced, thus causing different colors and racial features, and the language would have remained isolated for long enough that they would have begun to change, thus becoming modern the languages we know today in the many places around the world.
We can still see that all of mankind’s history came from one place. “If we look, first of all, for that part of the world which was the hothouse of the races, we can make only on choice. All the visible footsteps lead away from Asia.”-Anthropologist William Howell.
Then they would have begun to find iron ore and other such resources, begin to build homes, and then as they began to grow (remember they were highly advanced), they would have built cities, and tell the stories of the flood, which is where we derive the hundreds of documented flood legends. As more cities built we would soon have civilizations.
Andrew C. Abbott