CHAPTER XXIX 



THE VOICE 



" As the power of the vital soul is situated in the substance of the heart, and 

 the power of the natural soul in the proper substance of the liver, ... so also 

 does the brain, in appropriate structures and in organs properly subserving its 

 work, manufacture the animal spirit, which is by far the brightest and most 

 delicate, and indeed is a quality rather than an actual thing. And while on 

 the one hand it employs this spirit for the operations of the chief soul, on the 

 other hand it is continually distributing it to the instruments of the senses and 

 of movement. . . ." (1543) VESALIUS quoted by FOSTER. 



ARTICULATE speech may be considered as the resultant of 

 essentially two component factors, (a) the production of sound, 

 and (b) the modification of the sound to produce speech. 



I. The latter factor is the simpler and may be dealt with first. 

 Speech sound-units may be classed as vowels and consonants. 



The vowels, U, 0, A, E and I are produced by the continuous 

 issue of a blast of air through the mouth. U, and A, pro- 

 nounced 66 (cook), oh and ah, respectively, are simple tones. 

 They are produced by a regular series of vibrations emitted by 

 a single cavity formed by lips, cheeks, palate and tongue (Fig. 42). 



A (ah) 



U (M) 



FIG. 70. Changes in the Shape of the Mouth in Sounding the Vowels, A, U, and I. 

 (Grutzner.) 



This cavity is widest and shortest with A, longest and narrowest 

 with U, while is intermediate. On the other hand, E (as in 



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