What are the differences between the /u/ sound in ‘fool’ and the /ʊ/ sound in ‘full’?
Here are the differences between the /u/ sound and the /ʊ/ sound.
Vowel Length
The /u/ sound, as in ‘fool’, is a long vowel sound. The /ʊ/ sound, as in ‘full’, is a short vowel sound.
The /u/ sound is a tense vowel sound, which means that our lips and tongue muscles become tense. By contrast, the /ʊ/ sound is a lax vowel, which means that our lips and tongue muscles are relaxed in the production of this sound.
Tongue Height
Both of these sounds are high back vowels, which means that the back part of the tongue is high in the mouth. However, for the /u/ sound, the back part of the tongue is higher in the mouth than it is for /ʊ/. For the /u/ sound, the tongue pulls back and lifts towards the soft palate.
For the /ʊ/ sound, the back part of our tongue is high in the mouth, but not as high as it is for /u/.
Tongue: Frontness / Backness
For the /u/ sound, as in ‘fool’, our tongue is slightly further back in the mouth than it is for /ʊ/, as in ‘full’.
Lip position
For the /u/ sound, as in ‘fool’, our lips become tense and push forward into a tight circle. There’s more lip rounding in the production of /u/ than there is for /ʊ/. In the production of /ʊ/, as in ‘full’, our lips push forward away from the teeth, and there is some lip rounding, but not nearly as much as there is for /u/.
Practice
Luke /u/
I’d like to introduce you to my friend Luke.
Look /ʊ/
She gave me a strange look.
stewed /u/
The apples have been stewed.
stood /ʊ/
This is the place where she stood.
pool /u/
Let’s go for a dip in the pool.
pull /ʊ/
You push and I’ll pull.
fool /u/
I don’t want to look like a fool.
full /ʊ/
My stomach was full.
food /u/
We give the kids healthy food.
foot /ʊ/
I injured my foot.
Accent modification: ‘fool’ versus ‘full’