SPEECH 



409 



'2,000 d.v. and over per seeoiid. We w ill return to this iii dealing 

 with speeeh. 



Timbre or (juality of the voice depends largely on the accessory 

 resonating chambers. These cavities pick out and accentuate 

 the overtones produced by the vibrations of the segments of the 

 cords. Trained singers consciously or instinctively ada])t the 

 shape of the mouth so as to secure for each tone the most suitable 

 overtones. 



II. Articulate speech may be considered as the resultant of 

 essentially two component factors, {a) the production of sound, 

 and {h) the modification of the sound to produce speech. 



Speech sound-units may be classed as vowels and consonants. 



The vowels U, O, A, E and I are produced by the continuous 

 issue of a blast of air through the mouth. U, and A, pro- 



A {ah) U {oo) I (ee) 



Fig. 96. — Changes in the Shape of the Mouth in Sounding the Vowels, A, U, and I. (Griitzner.) 



nounced oo (cook), oh and ah, respectively, are simple tones. 

 They are produced by a regular series of vibrations emitted by 

 a single cavity formed by lips, cheeks, palate and tongue (Fig. 96). 

 This cavity is widest and shortest with A, longest and narrowest 

 with U, while is intermediate. On the other hand, E (as in 

 pet) and I (= ee) are double-toned. The back of the tongue is 

 brought up against the front part of the soft palate so that the 

 mouth is divided into two resonating cavities each with a charac- 

 teristic note (Fig. 96). 



By w^hispering the vowels one may readily determine the 

 resonance-pitch characteristic of each. U has the lowest pitch, 

 followed by O and A. It is thus easier to sing U and O on low 

 than on high notes. An attempt to go up the scale by sounding 

 " oos " will cause a tendency to clip the full vow^el and sound a 

 short " ee." The characteristic notes of each of these vowels 

 (by percussion, Expt. 72, p. 556) is given by Helmholtz as follows 

 (Fig. 97) : 



