SPEECH 327 



partly lost, the cords become altered and the cartilages ossify. 

 These circumstances make the voice weak and unsteady. 



Speech. Modifications and alterations of the sounds pro- 

 duced in the larynx during and after their production result, 

 under the influence of the sensorium, in articulate speech. 

 These modifications are made chiefly by the tongue, teeth, 

 and lips. 



The speech sounds are divided into vowels and consonants. 

 The distinction is that the vowel sounds are generated in the 

 larynx, while the consonant sounds are produced by altera- 

 tions in the current of air above the larynx, and cannot be 

 pronounced except constantly with a vowel. The current is 

 modified mainly by the tongue and teeth in the formation of 

 linguals and dentals, by the cavity of the nose in case of na- 

 sals, and by changes in the shape and size of the oral cavity 

 in the production of other sounds. 



Nervous Supply of the Larynx. The superior laryngeal 

 branch of the teeth is the sensory nerve, which guards the 

 glottis to prevent the entrance of foreign bodies. Impres- 

 sions made on the filaments of this nerve are reflected 

 through the medulla and inferior laryngeal branch of the 

 tenth to the muscles which close the glottis. The inferior 

 laryngeal also innervates the muscles that vary the tension 

 of the cords, and the superior laryngeal keeps the mind in- 

 formed of the state of the muscles and of the necessity for 

 forced expiration or coughing. 



