[u] ‘oo’ as in ‘boo’
The ‘oo’ as in ‘boo’ vowel sound. To make this sound, the back part of the tongue stretches up towards the soft palate, oo, oo. The front part of the tongue remains down, lightly touching, or just behind, the bottom front teeth, oo. And I’m sure you can see the lips round, oo, into a very tight circle for this sound, oo, boo.
Here is the ‘oo’ as in ‘boo’ vowel sound on the right compared with the mouth at rest on the left. You can see the corners of the mouth are pushed forward to round the lips. This pushes the center part of the lips away from the face. And here are the inside parts of the mouth drawn in. As with all vowels, the soft palate is raised. More importantly, note the tongue position: it is raised very high in the back. The tip of the tongue, however, is still touching the backside of the bottom front teeth. Sample words: spoon, tool, food. Sample sentence: Who’s in the mood for fruit? Now you’ll see this sentence up close and in slow motion, both straight on and from an angle, so you can really study how the mouth moves when making this sound.
Who, the mouth forms the oo sound. It’s spelled with a W but the two sounds are hh, the H and oo, the ‘oo’ as in ‘boo’. Who’s, the teeth come together to make the zz sound. In the, tongue comes through the teeth. Mood, another ‘oo’ vowel sound where the lips round, but the bottom lip begins already to move up to make the f sound, for, and again for the ff fruit, which has the ‘oo’ as in ‘boo’ vowel sound. And the lips come in and round. And the teeth come together – tt – to make the T sound.
And now from the angle. Oo, the tight circle of the lips, who’s. Teeth come together to make that Z sound, In the, lips come together for the M. And then the ‘oo’ as in ‘boo’ vowel, mood. And the bottom lip moves up to make the F, for, and one more time, fruit, with the ‘oo’ as in ‘boo’ vowel sound. The lips again make the tight circle and the teeth come together to make the T in fruit. That’s it, and thanks so much for using Rachel’s English.
International Phonetic Alphabet symbol: [u]
This sound exists in many languages. See Wikipedia’s page on it.