As you will have noticed, very often two vowels come next to each other in Spanish words. Unlike English which is much more variable, in Spanish these dual sounds are simply a combination or merging together of the two individual vowel sounds. In most cases these combinations are referred to as “diphthongs” but there are one or two pronunciation rules we need to look at to understand the subject properly.
For the purposes of this explanation we can divide the five Spanish vowels into two types: A, E and O are described as “strong” vowels. I also like to think of them as “open” vowels as you need your mouth wide open to pronounce them properly. On the other hand I and U are “weak” or “closed” vowels and in saying them our mouths are narrower and more closed.
The first thing we need to know about diphthongs is that any combination of one strong and one weak vowel produces a diphthong. These combinations therefore are: ai, ia, ei, ie, oi, io, au, ua, eu, ue, ou, uo. In addition we count iu and ui as diphthongs. The second thing to understand is that these combined sounds constitute a single beat or syllable. This is important to understand, particularly when we are applying the rules I mentioned in the last article about where the emphasis should go in a word.
To give some examples of what I am talking about, here are some words containing diphthongs which also show in bold and capital letters where the emphasis should go on the word. paiSAje; farMAcia; aCEIte; SEIte; OIga; paLAcio; autoBÚS; LENgua; EUro; PUEdo; CUOta; RUIdo; ciuDAD. In each case the diphthongs merge into a single dual sound creating a single syllable and the word emphasis follows the rules I have written about before.
In contrast to these examples, when we find two “strong” vowels together they stand on their own as single syllables. Hence: paSEo; oAsis, maREa and so on. One more thing to say is that a diphthong can be split into two syllables by use of an accent – hence panaderÍa; paÍs; grÚa; aÚn.
I realize that putting all of this together into one short article may seem rather too technical, but if you manage to get to grips with it all, your problems about how words should be pronounced will be over for ever.