There are thousands of languages spoken around the world today. While we know how many of them are related to each other, we know very little about how they actually arose. "The main reason is because we can't travel back in time and go back to the times when these languages actually emerged," said Manuel Bohn, a postdoctoral researcher at Leipsig University. There are languages, particularly sign languages, that have emerged over the past century. Even in those cases, though, Bohn says