DIPHTHONGS AND TRIPHTHONGS.

There are no Diphthongs or Triphthongs in the English sense of two or
three vowels meeting in one syllable and blending into a different
sound, as "pause," "plough."

Every vowel is pronounced separately and each with its alphabetical
sound, only the two or three vowels occurring in one syllable are
pronounced rapidly, as Pausa (pause), Reino (kingdom), Cuenta (account),
Buey (ox).

A, E and O never form diphthongs together. They may form diphthongs
and triphthongs only in combination with I and U.