Here's why:
* Schwa sound: The schwa sound (represented by the symbol ə) is a short, unstressed vowel sound. It's often described as the sound in the first syllable of "about".
* Adult: In "adult", the vowel sound is the long "u" sound, as in "flute". This is a distinct vowel sound and not the schwa.
So, the pronunciation of "adult" is /ˈædʌlt/, with no schwa sound present.