As a teenager, Harriet Shawcross stopped speaking at school for almost a year. As an adult, she became fascinated by the limits of language. From the inexpressible trauma of trench warfare and the aftermath of natural disaster, to the taboo of coming out, Harriet examines all the ways in which words scare us. She studies wartime poet George Oppen, interviews the author of The Vagina Monologues, meets Nepalese earthquake-survivors, and the founders of the Samaritans, and asks: what makes us silent?