The vowels are either long, short, or diphthongal. The resonances of the long vowels begin at the back, passing through the middle, to the front of the mouth. Thus:
The above represents the approximate and relative openings of the mouth in long vowels.
You notice the mouth aperture is narrow at the back, wide in the middle and narrow again at the front. For practice AW and AH and OO are the most valuable because the two chief difficulties of the student are; first, to open his mouth wide enough, and second, to keep his speech forward on the lips. Usually his speech is throaty. Practice the following in concert and individually in order to secure freedom in controlling the mouth:
1. Repeat E A AW AH O OO consecutively on the same pitch.
2. Change the pitch and repeat on each note of the scale.
3. Give a decided rising inflection to each vowel sound.
4. Give a decided falling inflection to each vowel sound.
5. Give a decided circumflex inflection to each vowel sound.
6. Blend them altogether by the straight inflection in a singing tone.