If three vowels belonging to the same word are contiguous, one of them
must be accented. There are then three possible arrangements.
(i) Three contiguous vowels of a word with the accent on the first,
e.g. _tráeos_.
(ii) Three contiguous vowels of a word with the accent on the second,
e.g. creia, _buey_.
(iii) Three contiguous vowels with the accent on the third, e.g.
_rehuí_.
Each of the above arrangements has two combinations of accented and
unaccented vowels to which the rules for diphthongs may be applied. In
(i) there will be a combination of two vowels with the first accented,
plus a combination of two vowels after the accent. In _tráeos_, for
example, the a and e would probably be in separate syllables by b (1)
(a), and eo would probably form a diphthong by c (1). _Tráeos_ would,
then, probably be a dissyllable.
In (ii) there will be a combination of two vowels with the accent an
the second, and one of two vowels with the accent on the first. In
creia, for example, the e and í would be in separate syllables by b
(2) (b), and the í and a would probably be in separate syllables also
by b (2)(a). Therefore, _creia_ would probably be a trisyllable. In
_cambiáos_ the i and á might form one syllable or two by b (2) (_d_),
and the á and o would probably be in separate syllables by b (1) (a).
Therefore, in _cambiáos_ the combination iáo might form a dissyllable
or a trisyllable.
In (iii) there will be a combination of two vowels before the accent,
and one of two vowels with the second accented. In _rehuí_, for
example, the e and u might be in the same syllable by a (1), or in
separate syllables by dieresis by a (1) (a), and the u and í might be
in separate syllables or not by b (3) (b). Therefore, _rehuí_ might be
a monosyllable, a dissyllable, or a trisyllable.
Other combinations of three vowels may be analyzed in a similar way,
as may also combinations of more than three vowels, e.g. _creíais_,
etc.