

THE VOICE AND SPEECH. 61 



differently modified in disposition. But the sound of the vowels, even 

 when mute, has its source in the glottis, though its vocal cords are not 

 thrown into the vibrations necessary for the production of voice; and the 

 sound seems to be produced by the passage of the current of air between 

 the relaxed vocal cords. The same vowel sound can be produced in the 

 larynx when the mouth is closed, the nostrils being open, and the utter- 

 ance of all vocal tone avoided. This sound, when the mouth is open, is 

 so modified by varied forms of the oral cavity, as to assume the characters 

 of the vowels a, e, i, o, u, in all their modifications. 



The cavity of the mouth assumes the same form for the articulation 

 of each of the mute vowels as for the corresponding vowel when vocal- 

 ized; the only difference in the two cases lies in the kind of sound emitted 

 by the larynx. Krantzenstein and Kempelen have pointed out that the 

 conditions necessary for changing one and the same sound into the differ- 

 ent vowels, are differences in the size of two parts the oral .canal and 

 the oral opening; and the same is the case with regard to the mute vowels. 

 By oral canal, Kempelen means here the space between the tongue and 

 palate: for the pronunciation of certain vowels both the opening of the 

 mouth and the space just mentioned are widened; for the pronunciation 

 of other vowels both are contracted; and for others one is wide, the other 

 contracted. Admitting five degrees of size, both of 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 canal. 



a as in "far" 5 ... 3 



a " "name" 4 ... 2 



e " "theme" 3 .... 1 



o " "go" 2 ... 4 



oo " "cool" 1 ... 5 



Another important distinction in articulate sounds is, that the utter- 

 ance of some is only of momentary duration, taking place during a sud- 

 den change in the conformation of the mouth, and being incapable of 

 prolongation by a continued 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, I. Corresponding differ- 

 ences in respect to the time that may be occupied in their utterance exist 

 in the vowel sounds, and principally constitute the differences of 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 "rotten," cannot be prolonged. 



