Vowels which have a single vowel sound when pronounced are called pure vowels. The twelve vowel sounds we have mentioned earlier are pure vowels. Words such as announce(ə), fret(e), sun(ʌ), tick(ɪ), please(iː), dot(ɒ), foot(ʊ), food(uː), word(ɜː), warm(ɔː), arm(aː) and pant(æ) come under this category.