PHOnetics 1

BACK VOWELS
Now pronounce the sound you make when you say “aw”, as in “AW, come on”. Pronounce the final sound of “too”. For this vowel, the lips are rounded and the back of the tongue is raised to a place near the velum, leaving a little space for the air to flow.
As the back of the tongue is lowered from the / u: / position, it reaches in turn the positions for the three other back vowels = / U / as in pull, / o / as in note, and / O / as in law. And at each of these three positions the rounding of the lips is successively opened, as you can observe in the mirror. The four back vowels, from top to bottom, are illustrated by this series:
fool = / u: /, full = / U /, foal = / o /, fall = / O /

CENTRAL VOWELS
English has three central vowels if you pronounce “fur”, “sir”, “her”, you are uttering, as the final sound, a mid-central r-colored vowels , / «r /.
The second central vowel may be illustrated by the first sound of “up”. It is heard as the pronunciation of the underlined vowels in the following words.

Stressed: / ¿ / sun, done, flood.
Unstressed: / « / sofa, alone, about, around, garbage.
The / « / is a vowel of high frequency in English, especially in unstressed syllables, and is technically called “schwa”.
The third central vowel is the sound you make when the doctor says, “Open your mouth and say a-a-a”. For most Americans this is the vowel of “father”. It’s symbolized by this series.
nurse = / «r /, nut = / ¿ /, not = / a /.