212 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



There are two kinds of speech — viz., vocal and whis- 

 pered. The one is the articulation of the voice, the 

 other of the aspiration. 



Speech may be denned as a succession of vowel 

 sounds interrupted and separated by consonants. Vowels 

 are modifications of the voice. Consonants are the modes 

 of interruption. There are two kinds of modifications of 

 the voice — viz., modification of pitch, high or low, and 

 modification of the timbre or quality of the voice. The 

 former is done in the larynx, as already explained; the 

 latter is done by changes in the mouth cavity. The vowels 

 are modifications in timbre, not in pitch. The larynx 

 has nothing to do with it. We have a good illustration 

 of what we mean by timbre in the sounds of different 

 musical instruments. The same musical note may be 

 made on the flute, the clarionet, the violin, or the bugle, 

 but how different is the quality of the sound in each case ! 



Vowels. — We give a series of seven vowels in such 

 order as to show and easily describe the changes in the 

 mouth cavity, thus: e, a, ah, au, d, oo, u. (i) Bring the 

 teeth near together, retract the lips a little, bring the 

 tongue forward until it nearly touches the teeth, and 

 then make a sound with the larynx; the sound is the 

 long ee, and can not be anything else. (2) Other things 

 remaining the same, separate the teeth a little more and 

 draw back the tongue a little, and make a sound of the 

 same pitch; the sound now appears as a in fate, and can 

 not be anything else. (3) Open the mouth much wider, 

 draw back the tongue still more, and again make a 

 sound of the same pitch; it comes out now as a in far, 

 and it can not be anything else. (4) Separate the jaws 

 as much as possible, draw back the tongue as far as 

 possible, but bring the lips a little nearer together in 

 front ; and the same note now becomes au in awe. (5) 

 Now bring the jaws again a little more together and the 



