When you wave to someone, that can also mean "hello." Humans started writing about 5,000 years ago. Language is a way for people to communicate. Writing came later. Many languages borrow words from others. These handy devices were first called "cellular phones." It was first used by early human ancestors. They are able to understand language. They change and shorten existing words, too. This might happen when people who speak different languages are trying to communicate with one another. Language made it possible for humans to develop societies. You don't have to say "yes" at the same time to get your message across. These mixtures are called pidgin languages. Babies can not speak right after they are born. This is true for writing and sign language, too.