Genesis claims that the descendants of Noah's three sons spread out and repopulated the earth according to their families, tongues, lands, and nations.
The passage Genesis 10, sometimes called the "table of nations, lays out this history.
The descendants of Japheth, or "coastland peoples," settled along the Mediterranean coast, Asia Minor, and northern Mesopotamia. From them emerged the Europeans and Iranians.
The descendants of Ham settled in Canaan, Africa, and across the fertile crescent. Again, the bible attributes the establishment of cities to individuals. According to this account, the descendants of Ham built the ancient cities of Babel, Erech, Accad, and Nineveh. From them emerged the Africans and some Middle Eastern peoples.
Finally, the descendants of Seth settled through out the Mesopotamia and the Arabian peninsula. From them emerged most Middle Eastern peoples, including those fightin' cousins--the Hebrews and the Arabs.
Each account of the descendants of Noah's sons is said to be "after their families, after their tongues, in their countries, and in their nations."
Only in the next chapter does the bible attempt to explain the origin of the families, tongues, countries, and nations. And as one might suspect, the account differs from reality.
The people, according to this addition, spoke one language. Their migrations after the flood brought them to Shiner or Babylonia. Once there, the embarked on an ambitious project.
"And they said one to another, Go to, let us make brick, and burn them thoroughly. And they had brick for stone, and slime had they for mortar. And they said, Go to, let us build us a city and a tower, whose top may reach unto heaven; and let us make us a name, lest we be scattered abroad upon the face of the whole earth." Genesis 11:3-4
In accordance with the primitive biblical belief in a flat earth covered with a dome, the inhabitants believed that they could build a tower to reach the dome. And God thought so, too.
"And the Lord came down to see the city and the tower, which the children of men builded. And the Lord said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do." Genesis 11:5-6
Alarmed at the progress, God decided to confound their speech so that they could no longer cooperate with each other.
"Go to, let us go down, and there confound their language, that they may not understand one another's speech. So the Lord scattered them abroad from thence upon the face of all the earth: and they left off to build the city. Therefore is the name of it called Babel; because the Lord did there confound the language of all the earth: and from thence did the Lord scatter them abroad upon the face of all the earth". Genesis 11:7-9
Without the ability to communicate, the people stopped building their tower and resumed their migrations. (And it might be added, instead of cooperation, mankind became subject to misunderstanding, division, and warfare.) Consequently, they allegedly settled themselves according to the pattern described in the previous chapter. In this way, the ancient Hebrews came to explain the origins and presence of the surrounding peoples.