There is always triphthongal synalepha when a is the middle vowel; or
when o or e is the middle vowel, except in the following combinations,
aoa, aoo, ooo, aea, aeo, oea, oeo.
Ex. _Silenciosa á expirar_, p. 178, XXXVII, l. 20.
There is never triphthongal synalepha when an accented weak vowel
stands between two strong vowels. Therefore the conjunctions y and ú
prevent triphthongal synalepha.
Ex. _Y de purpura y oro la matiza_, p. 168, IX, l. 4.
There may be triphthongal synalepha when í (y) is the middle vowel, if
u precedes it, or i follows it.
Ex. _Fuí diestro, fuí valiente, fuí arrogante_. Cervantes.
When u is the middle vowel there may be synalepha if i follows it. The
construction is very rare.
There is no synalepha with a word beginning with hue.
Ex. _Mucho nuestro huesped tarda_. Tirso de Molina.
In the following cases the groups of vowels which would usually make
triphthongal synalepha are pronounced in two syllables:
(1) When the first word of the group ends in two vowels which do not
form a diphthong.
Ex. _Que aún tení|a^abiertos_, p. 187, LXXIII, l. 2.
(2) When the two initial vowels of the second word do not form a
diphthong.
Ex. _Tú, sombra^a|érea que, cuantas veces_, p. 170, XV, l. 7.
(3) When the first word ends in a diphthong and the second begins with
a vowel in a constituent syllable (i.e. a syllable on which the
rhythmical accent falls).