Barry Smith argues that language is our most important uniquely human attribute. It doesn't just help us communicate, it helps us to think. He makes the case for the distinctiveness of human language against the limited signalling systems of other animals. He looks at Noam Chomsky's idea of a universal grammar – that there is something in the human brain that gives us an innate ability to produce language from very early in our lives. And he talks to experts on other intelligent animals - Prof. Nicola Clayton and Prof. Robin Dunbar - to ask how human language and imagination compares with that of birds and primates.