Stuttering as a disorder has nothing to do with anxiety or nerves. They can make it worse, but they aren’t the root cause. What the root cause is, we don’t know, but we know that there are strong genetic links, and measurable differences in neuroanatomy compared to people who don’t stutter. As far as we can tell it’s a breakdown in the execution of planned speech somewhere. This idea that everyone who stutters is nervous is prevalent and comes from people who don’t have the disorder — they do stutter when they re nervous, or afraid, and so they assume that people with the disorder must always be nervous. The King’s Speech is a good movie, and definitely one of the better movies to feature stuttering, but it’s really hit or miss on therapy techniques. Some of what’s in it are real and still used, and a lot of what’s seen is nonsense made up for the camera.