To speak correct Spanish it is necessary to study little phonetics of Spanish, to practise the pronunciation and the intonation of the words and to know as there are the sounds of the Spanish language.
In Spanish, the vowels are five:
to, and, i, o, u
And the five declare themselves as such. One to is always pronounced how to, one and as and, etc.
Five vowels qualify like strong (keynotes) or (unstressed) dweebs. When the keynotes are pronounced the mouth is very open or moderately open. There are a syllable nucleus.
Three tonic vowels are:
and, to, or
In case of the unstressed vowels, the mouth is more closed when we pronounce them. Two unstressed vowels are:
, , , , , , , , , , , , , ,