These five sounds never vary, except that they are a little longer when they are stressed and shorter when they are not, as Yo amo (I love),[3] Amigo (friend), El cielo (heaven), Celeste (heavenly), Un recibo (a receipt), Interés (interest), Yo como (I eat), Contar (to count), Un buque (a ship), Una butaca (an armchair).
Y is considered a vowel in the conjunction y (and), and at the end of a word, as Rey (king), Hoy (to-day).
[Footnote 1: E and o are sounded a little more open when they form a diphthong with i and when they precede r followed by a consonant or r or l final, as Fernando (Ferdinand), Un tercio (a third), El tercer año (the third year), Porfiar (to insist), Amor (love), Español (Spanish).]
[Footnote 2: The a and o of "fate" and "note" are not pure vowel sounds. In English the a is distinctly pronounced a-ee and o is pronounced o-oo.
In Spanish the first part only of the two sounds is permissible.]
[Footnote 3: The examples given with their English equivalents should be learnt.
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.