Identical twins Matthew and Michael Youlden invented their own private language as toddlers. They’ve gone on to become accomplished multi-linguists, but kept up their childhood invented language and still use it today.

Matthew Syed explores the extraordinary human capacity to invent new systems of communication and considers whether language can penetrate and shape the way we see the world.

He discovers the fascinating process involved in developing fictional languages with language creator Jessie Peterson. She invented ‘Firish’ (or Ts'íts'àsh), which is spoken by the animated fire beings in Disney’s Elemental. Matthew also hears about the life-changing effect the ancient language of Sanskrit had on an American Professor. Through their stories, Matthew rethinks his own feelings towards the relationship between language and thought.

With identical twins ‘Superpolyglot Bros’ Matthew and Michael Youlden; Professor of Psychology and Director of the Twin Studies Center at California State University Fullerton, Dr Nancy Segal; professional language creator Jessie Peterson; and Varun Khanna, Professor of Classics at Swarthmore College, Pennsylvania.

Presenter: Matthew Syed Producer: Vishva Samani Editor: Hannah Marshall Sound Design and Mix: Mark Pittan Theme music by Ioana Selaru A Novel production for BBC Radio 4