VOICE 279 



being true octaves, do not blend either with the funda- 

 mental tones or with each other. Under these circum- 

 stances, the voice is unmusical and harsh. An inflam- 

 matory condition of the throat, as in a cold, may result 

 in the swelling of the vocal cords (laryngitis), which 

 produces the same result. 



Effect of air cavities upon the voice. It has been 

 found by experiment that the various cavities of the 

 mouth, nose, trachea and lungs have a tendency to act 

 as organ pipes for the reinforcement or increase of the 

 vocal sounds, in just so far as the air within them tends 

 to vibrate in unison with the fundamental vibrations of 

 the vocal cords and of their overtones. In this way, the 

 quality of the voice is made richer and its volume 

 greater. The assistance given by the cavity of the nose, 

 for example, may be readily appreciated by contrasting 

 a person's ordinary voice with the voice produced when 

 the nose cavity is closed by pinching the nostrils or by 

 a head cold. The nasal twang of many voices is due 

 to the fact that the nose is not properly open. 



Vowels. Besides the increase and reinforcement of 

 the vocal sounds by the air in the various cavities, cer- 

 tain parts of the throat, tongue and lips modify and 

 interrupt the sounds produced. When the air passages 

 are unobstructed so that the movement of the air is 

 continuous, the sounds made are called vowels. One 

 can readily observe with a mirror the changes involved 

 in the production of the sounds a, e, i, o and u. 



Consonants. The consonants, on the contrary, are 

 produced when the air passages are partially or com- 

 pletely obstructed, as by the lips and tongue. If the 

 closure is complete and then is suddenly overcome by 

 air pressure, we get an explosive articular sound, such 

 as is required for the pronunciation of the consonants 



