Stammering is an impediment of thought, not of speech. Analogous disturbances manifest themselves in swallowing, breathing, walking, writing, etc. There are numerous exciting causes of stammering, some of the common being fright, imitation, language difficulties and illness. All cases are made worse by excitement. The essential mechanism of stammering is found in a blocking of mental images. In mental imagery the mental word consists of two parts: the auditory image (sound of the word as it falls on the ear) and the motor image (feeling of speech movements as they occur at the lips, tongue or throat). At times the motor image alone is recalled and the auditory image is lacking. There is, then, a break in consciousness, a blocking of thought that results in stammering. Underlying the disturbance of thought is a neurotic temperament.
The treatment is thought training rather than speech training; it is a matter of drilling