In Italian, all consonants except h can be doubled. Double consonants (i consonanti doppie) are pronounced much more forcefully than single consonants. With double f, l, m, n, r, s, and v, the sound is prolonged; with double b, c, d, g, p, and t, the stop is stronger than for the single consonant. Double z is pronounced almost the same as single z. Double s is always unvoiced.

Double consonant examples:

Most Italian words end in a vowel.

Diphthongs (i dittonghi) are two vowels fused to emit a single sound. A diphthong is formed when an unstressed i or u combines with another vowel (a, e, o) or when the two vowels combine with each other, in which case either the i or u may remain unstressed. In diphthongs, unstressed i and u become semivowels approximating in sound the English consonants y and w, respectively.

Diphthong examples:

Tripthongs also exist. These are sequences of three vowels with a single sound, usually a diphthong followed by an unstressed i.

Italian has numerous words that contain sequences of vowels. The following words are not triphthongs (which are infrequent), but sequences of a vowel and a diphthong.

Each of the words below has a sequence of two diphthongs: