For example, English has 26 consonants, 12 vowels and three diphthongs, even though there are only 26 letters in the English alphabet.
See:
... winner of the Nobel Prize in literature May 11 - Salvador Dalí, artist May 17 - Jean Gabin[?], actor (+ 1976) May 21 - Fats Waller, pianist (+ 1943) May 21 ...