As humans, our ability to speak in full sentences may be the reason why so many people are right-handed. On the blog Developing Intelligence, Chris Chatham, a University of Colorado graduate student, wrote that a preference for the right hand evolved when humans developed of language. Chatham dug up a paper from 2003 saying that the reason why so many people are right handed, and so many other animals are not, is because both communication and the right hand are controlled by the left side of the brain. As humans evoleved, and communication skills improved, so did the left side of our brains, making more people right handed.
—Eric Kelsey
