556 MUSCLE-NERVE PHYSIOLOGY 



the opening of the mouth and of the space between the tongue and palate, 

 Kempelen thus states the dimensions of these parts for the following vowel 

 sounds: 



Vowel. Sound. Size of oral opening. Size of oral canah 



a as in "far" 5 3 



a as in "name" 4 2 



e as in "theme" 3 i 



o as in "go" 2 4 



oo as in "cool" i 5 



Another important distinction in articulate sounds is that the utterance of 

 some is only of momentary duration, taking place during a sudden change in 

 the conformation of the mouth, and being incapable of prolongation by a con- 

 tinued expiration. To this class belong b, p, d, and the hard g. In the 

 utterance of other consonants the sounds may be continuous; they may be 

 prolonged, ad libitum, as long as a particular disposition of the mouth and a 

 constant expiration are maintained. Among these consonants are h, m, n, 

 f, s, r, 1. Corresponding differences in respect to the time that may be oc- 

 cupied in their utterance exist in the vowel sounds, and principally constitute 

 the differences between long and short syllables. Thus the a as in far and 

 fate, the o as in go and fort, may be indefinitely prolonged; but the same 

 vowels (or more properly different vowels expressed by the same letters), 

 as in can and fact, in dog and gotten, cannot be prolonged. 



All sounds of the first or explosive kind are insusceptible of combination 

 with vocal tone (intonation), and are absolutely mute; nearly all the con- 

 sonants of the second or continuous kind may be attended with intonation. 



The tongue, which is usually credited with the power of speech, plays 

 only a subordinate, although very important, part. This is well shown by 

 cases in which nearly the whole organ has been removed on account of 

 disease. Patients who recover from this operation talk imperfectly, and 

 their voices are considerably modified; but the loss of speech is confined 

 to those letters in the pronunciation of which the tongue is particularly 

 concerned, namely, c, d, g, h, j, k, etc. 



Stammering depends on a want of harmony between the action of the 

 muscles (chiefly abdominal) which expel air through the larynx, and that of 

 the muscles which guard the orifice (rima glottidis) by which it escapes, and 

 of those (of tongue, palate, etc.) which modulate the sound to the form of 

 speech. Over either of the groups of muscles, by itself, a stammerer may 

 have as much power as other persons, but he cannot harmoniously arrange 

 their conjoint actions. 



