Jamieson, Fausset and Brown on Genesis 10:32

32. These are the families of the sons of Noah, after their generations, in their nations, &c.--This division was made in the most orderly manner; and the inspired historian evidently intimates that the sons of Noah were ranged according to their nations, and every nation ranked by its families, so that every nation had its assigned territory, and in every nation the tribes, and in every tribe the families, were located by themselves.