Perhaps the most striking sign of mobility is the fact that by the third millennium B.C., most pastoralists in this huge region spoke related languages ancestral to the modern Indo-Europeanlanguages.
He also examines the comparative structure of Indo-Europeanlanguages and East Asian languages, finding important differences which to some extent parallel differences in thought processes.
Further research, carried out by the German brothers Grimm and others, later revealed that most Europeanlanguages and some Indian ones have a common ancestor, now known as Indo-European.