This Chapter from the Yellow Emperor's Classic of Internal Medicine explores the physiological causes of sudden voice loss. The text details the anatomical structures involved in speech production, including the throat, epiglottis, and tongue, and their roles in the flow of qi. It then proposes a diagnosis of cold qi obstructing the epiglottis as the cause of this ailment and recommends acupuncture treatment targeting specific meridians to resolve the blockage and restore voice.