SOUND PRODUCTION AND SPEECH 



745 



Vowels. The vowels are tones produced in the larynx, and 

 modified by the form of the resonating cavity. The consonants are 

 in the main noises produced by alterations in the resonating cavity, 

 alterations which momentarily check the air blast, and so lead to an 

 explosive sound, or lead to the vibration of lips or tongue, as the air 

 rushes through orifices which are of changing form. 



A (ah) : The mouth is opened funnel-shaped from behind forwards, 

 the tongue lies flat on the floor. 



(go): The mouth opens by a narrow slit, the jaws and lips being 

 approximated; the tongue is drawn back so that the mouth becomes 

 a long oval cavity. 



U (too) : The lips are still more approximated and are protracted, 

 the tongue pulled back and arched still more. The cavity is like a 

 round flask with two orifices a wider inlet and a narrow outlet. 



Fio. 456. SHAPE OF MOUTH IN SOUNDING DIFFERENT VOWELS. 



A (pay): The point of the tongue approximates to the hard palate, 

 leaving a slit-like canal; the root of the tongue sinks. The mouth 

 cavity takes the shape of a small-bellied flask with a short and some- 

 what narrow neck. 



E (me): The point of the tongue comes still nearer to the hard 

 palate, while the root of the tongue is still further pulled down. The 

 mouth is thus made a larger cavity, but with a longer and narrower 

 neck. 



The diphthongs are produced by the passage from one vowel 

 sound to another, and cannot therefore be sustained on one note. 



Sound is reflected when it strikes against a smooth surface, such 

 as a wall. From the walls of an enclosure sound may be reflected to 

 and fro, and the series of echoes will produce a musical note, the pitch 

 of which will not change at the moment when that of the musical 

 note is changed, for it is produced by the number of echoes per minute. 



By taking a number of jugs and vases and sounding a musical note 

 into each, one can recognize each vase by the characteristic sound 

 it produces. So are the vowels recognizable, produced as they are 

 by the varying- shaped cavity of the mouth. 



