Hello, welcome to the witness history podcast from the BBC World Service. Today we're

taking you back to the 1980s when deaf children in Nicaragua invented a brand new sign language

of their own. It gave experts a unique insight into how human communication develops.

In 2020, Mike Lanchin spoke to American linguist Judy Sheppard Kegel who documented this process.

My little linguist brain looking at them signing to each other was going, okay, here's all this

is happening, this is that rule, this is what's happening with the grammar. You could see the ease

of communication, you could see the understanding that they all understood each other. In the mid

1980s American linguist Judy Sheppard Kegel was standing in a playground full of deaf children

in Managua Nicaragua when she witnessed an exciting and enthralling development. The deaf youngsters

were inventing their own sign language. And I realized, whoa, we are seeing the emergence of a

language. This was something that needed to be documented. The emergence of new languages is not

unknown, but it's never been the case that someone has actually been able to film, document,

and follow the process of what the human brain is doing with language. But how and why did a

new sign language emerge from this tiny, impoverished Central American country? In 1979 Nicaragua

underwent a huge change as left-wing Sandinista rebels ended decades of rule by the brutal Samoza

dictatorship. The new revolutionary government had an agenda of education for all and sent students

out into the countryside to teach the peasants to read and write. But also Nicaragua's disparate

deaf community was for the first time offered the chance of vocational training and schooling.

Deaf children prior to the 1980s were extremely isolated. They were isolated from language and

they were isolated from the community. All they had was a handful of gestures. They maybe had

five to ten gestures, something like, I want to eat, or I have to go to the bathroom. I mean,

just gestures that were used in the family. And certainly, there were very, very few deaf people

...