514 VOICE AND SPEECH. 



variations in pronunciation ; but these do not belong to the 

 subject of physiology. There are, however, certain natural 

 divisions of the sounds as expressed by the letters of the 

 alphabet. 



Vowels. Certain articulate sounds are called vowel, or 

 vocal, from the fact that they are produced by the vocal 

 chords, and are but slightly modified as they pass out of the 

 mouth. The true vowels, a, e, i, o, u, can all be sounded 

 alone, and may be prolonged in expiration. These are the 

 sounds chiefly employed in singing. The differences in 

 their characters are produced by changes in the position of 

 the tongue, mouth, and lips. The vowel-sounds are neces- 

 sary to the formation of a syllable, and although they are 

 generally modified in speech by consonants, each one may, 

 of itself, form a syllable or a word. In the construction of 

 syllables and words, the vowels have many different quali- 

 ties, the chief differences being as they are made long or 

 short. In addition to the modifications in the vowel-sounds 

 by consonants, two or three may be combined so as to be 

 pronounced by a single vocal effort, when they are called 

 respectively, diphthongs and triphthongs. In the proper 

 diphthongs, as oi, in voice, the two vowels are sounded. In 

 the improper diphthongs, as ea, in heat, and in the Latin 

 diphthongs, as se, in Caesar, one of the vowels is silent. In 

 triphthongs, as eau, in beauty, only one vowel is sounded. 

 Y, at the beginning of words, is usually pronounced as a con- 

 sonant ; but in other situations it is pronounced as e or i. 



Consonants. Some of the consonants have no sound in 

 themselves, and only serve to modify vowel-sounds. These 

 are called mutes. They are b, d, k, p, t, and c and g hard. 

 Their office in the formation of syllables is sufficiently 

 apparent. 



The consonants known as semi-vowels are, f, 1, m, n, r, 

 s, and c and g soft. These have an imperfect sound of 



