Well, somewhere about 8000 B. C., then, bands of proto-Mongolians began to filter in through the easy, northwest gate of America. Others pushed them behind; before them, to the south, the country was ever more pleasantly tempting, and life easier. They multiplied, streamed down the Pacific coast, wandered across to the Atlantic, entered the tropics in fertile Mexico, defiled through Panama, and slowly overran South America. Separate groups of entrants into Alaska may have brought distinct languages with them; or, if they all came with one mother-tongue, their migrations to diverse environments and long, long separations provided ample opportunity for differentiation into dialects, languages, and families. The history of speech in the Old World covered by records, is but little more than three thousand years old, just a third of the ten thousand years with which we are dealing in America. Multiply by three the difference between twentieth-century English and ancient Sanskrit or one of its modern representatives such as Bengali, and there is just about the degree of speech distinctness that exists between the American language families, such as Siouan and Algonkin, Aztec and Maya.