This section is from the book "The Home Hand-Book of Domestic Hygiene and Rational Medicine. Volume 2.", by J. H. Kellogg, M.D.. Also available from Amazon: The Home Hand-Book of Domestic Hygiene and Rational Medicine, Volume 2.
We have already considered loss and impairment of the voice from disease of the vocal apparatus and from paralysis of the nerves which control the muscles of speech, under the head of "Aphonia." We have now to consider other disturbances of speech which arise from disease of some part of the nervous apparatus involved in speech production. Of the numerous disorders which have been described by systematic authors we will mention some of the most important.