This programme looks at the ways language is used and abused. While not everyone approves of 'bad' language, Stephen learns that swearing plays an important part in human communication the world over. He undergoes an MRI scan and discovers the parts of the brain associated with swearing - and meets a sufferer of Tourette's and a stroke patient who swear they can't help using the f-word. Stephen and Brian Blessed participate in some rather colourful experiments to examine how swearing can help relieve pain. Stephen discusses the positive and negative power of 'bad' words in humour and social interactions with Armando Iannucci, Stephen K Amos and Omid Djalili, and discovers how we use double entendres, euphemisms, and politesse to hide true meanings. Stephen meets nurses, teenagers, and rappers to discover how slang and jargon can both aid and thwart clear communication, but ultimately add to the richness and texture of language.