A. DIPHTHONGIZATION
Mute h between vowels is disregarded and does not prevent diphthongization, e.g. a^h^ora, re^h^usar.
The separation of two vowels that are usually united in one syllable is called diaeresis, e.g. vi|oleta.
The union in one syllable of two vowels that are usually in separate syllables is called synaeresis, e.g. ca^os.
1. THE TWENTY-FIVE POSSIBLE COMBINATIONS OP VOWELS IN DIPHTHONGS
The vowels may be divided into strong vowels (a, e, o) and weak vowels (i, u). For purposes of versification y as a vowel may be treated as i. The five vowels (a, e, o, i, u) taken in pairs may form diphthongs in twenty-five possible combinations, as follows:
a. Pairs of two weak vowels: ui, iu, ii, uu.
b. Pairs of two strong vowels:
{ ae, ao, aa,
{ ea, eo, ee,
{ oa, oe, oo.