312 PHYSIOLOGY. 



together with the size and condition of the cords them- 

 selves. 



Pitch of Voice. Pitch depends on the rapidity of the 

 vibrations, which is determined by the length of the cords 

 and their tension. Other things being equal, the size of 

 the larynx would determine the pitch. 



Voice and Speech. The larynx by itself produces 

 vocal sound merely. In speech the sounds produced in 

 the larynx are much modified by the lips, tongue, teeth, 

 cheeks, etc. We have voice as soon as born, but we only 

 gradually acquire the power of speech. Mammals, birds, 

 and some of the lower vertebrates have voices, but they 

 have not speech. This distinguishes man from the ani- 

 mals below him, though perhaps some of the higher apes 

 have speech in a slight degree. Dogs can express their 

 wants by barking, growling, snarling, etc., but it is mostly 

 by their tone, with their attitudes, and a slight facial 

 expression (as in snarling). 



Vowels and Consonants. By various positions of the tongue and 

 organs of the throat we make the different vowel sounds. In the con- 

 sonants we more or less shut off (for the time) the passage of air, and 

 so stop, or modify, the sound. This is hardly the place to study and 

 analyze the sounds of our spoken language, yet it may be found profita- 

 ble to watch the different organs as each sound is produced ; for when 

 the structure and relation of the different parts concerned in the pro- 

 duction of these sounds are better known, the definitions and state- 

 ments of the books will be much more fully understood. 



Differences between Voices. Since no two throats 

 are exactly alike, no two voices sound just the same. The 

 size and shape of the pharynx, the shapes and positions of 

 the teeth, lips, the condition of the mucous membrane of 

 the passages generally, all affect the sound, and give it its 

 " quality," by which we distinguish one voice from another, 



