CHAPTER X. 



THE LARYNX AND THE PRODUCTION OF 

 ARTICULATE SPEECH. 



The only property which man possesses par excellence 

 to the exclusion of all other animals is that of ' articulate 

 speech. The voice is something which belongs to the 

 human larynx alone. Many of the lower animals are able 

 to produce characteristic sounds, and these sounds some- 

 times, as in the case of birds, may extend through quite a 

 wide scale and be of a complicated character; but it goes 

 without question to say that they possess none of the real 

 peculiarities of articulate speech. The human voice con- 

 sists of sounds which are produced by the vibrations of two 

 elastic bands called the vocal cords placed in the voice- 

 box. This voice-box, or larynx, is really no more than a 

 dilatation of the upper portion of the trachea so arranged 

 with a series of cartilage as to enable the air driven through 

 it to set the vocal cords in vibration. The consideration 

 of the voice immediately after the subject of respiration, is 

 based upon its somewhat secondary connection with the 

 trachea and lungs. Fundamentally the physiology of res- 

 piration and that of articulate speech have nothing in 

 common. 



The vocal cords vibrating alone would produce but 

 feeble sounds quite different from the ordinary sounds of 

 the voice. The vibrations of the vocal cords are, there- 

 fore, strengthened by resonance cavities, like the vibrations 

 of a violin string are very integrally strengthened by the 

 resonance of the violin frame underneath, or as the note of 

 an organ pipe is very dependent indeed upon the resonance 

 cavity in the long tube of the pipe in question. The reso- 

 nance cavities for the vocal cords are the larynx itself, the 



(239) 



