VOICE AND SPEECH. 73 



mouth so as to become articulate, constitute "speech." 

 Articulation consists in the production of certain sounds 

 in the mouth and pharynx which are either associated 

 with voice (as in speaking aloud), or constitute all that is 

 heard (as in whispering). These sounds are distinguished 

 as vowels and consonants. Vowel sounds differ from con- 

 sonant sounds in possessing the characters of musical 

 tones, and may accordingly be distinguished by the rela- 

 tive vibration rates of the tones which constitute them. 

 Each vowel has its own pitch or tone. To produce any 

 vowel sound, such form must be given to the cavity of the 

 mouth and pharynx as to render it a " resonator " for the 

 tone which is characteristic of the vowel to be produced. 

 Consonants are modifications of the voice or whisper caused 

 by the passage of air through constricted or valvular parts 

 of the mouth or fauces. They derive their characters 

 from the duration and order of succession of the sounds 

 which constitute them. They are produced by the soft 

 palate, tongue or lips. They are divisible into four groups, 

 viz. (i) valve sounds, (2) blowing sounds, (3) nasal sounds, 

 (4) vibrating sounds. Of these groups each of the sounds 

 belonging to the first and second, presents itself in a soft 

 and a hard modification, of which the former cannot be 

 adequately produced in a whisper. This classification 

 does not include the aspirate H, which consists in the 

 production of an expiratory sound in the larynx, imme- 

 diately preceding that of the vowel sound aspirated. 



