Stuttering is as old as human speech. The biblical Moses stuttered. Winston Churchill, Marilyn Monroe, King George VI and James Earl Jones were also afflicted with the disorder--yet it remains a medical enigma. Unspeakable examines the nature, history and treatment of a speech impediment that affects about 1% of the world’s population regardless of language, culture, class or ethnicity. Throughout the ages there have been all sorts of explanations for what causes stuttering but attempts at curing it have been as frustrating as finding its cause. While stuttering inevitably causes emotional distress, which aggravates the disorder, there is no evidence …