What is vowel sound?

A vowel sound is an exhalation of air where a sound is produced in the larynx (voicebox) rather than being shaped by the nose and mouth (tongue, lips, teeth).

It is possible to say all of the long and short vowel sounds, and some of the special sounds, with a completely open mouth:

Long sounds : A, E, I, O, OO,

Short sounds ah, eh, ih, aah (as in odd), and oah (as in good).

Caret O (OR in the UK, sounds long) : aw