Witnessing the birth of a new language

In the early 1980s deaf children in Nicaragua invented a completely new sign language of their own. It was a remarkable achievement, which allowed experts a unique insight into how human communication develops. Mike Lanchin has been speaking to American linguist Judy Shepard-Kegl, who documented this process and says "our belief is that you are born with a language-ready brain". (Photo credit should read INTI OCON/AFP via Getty Images)