We now turn to a very interesting phenomenon which is somewhat disconcerting for Spanish speakers: the pronunciation of English triphthongs. Being aware of it will help you not only to sound more natural and fluent but also to understand what native speakers say better.
English has five triphthongs, which are formed by the diphtongs ending in /ɪ/ and /ʊ/ + the sound /ə/. Let’s see some examples:
As you can see, triphthongs have three vowel sounds in a row. However, they are not always fully pronounced since very often the second element (that is, the [ɪ] or [ʊ] in the middle) is considerably weakened or left out altogether. This process is called smoothing and it is very typical of British RP (it occurs less frequently in General American).
The smoothing phenomenon particularly affects the diphthongs /aʊ/, /aɪ/ and /eɪ/, which become [aə], [aə] and [eə]. So, the result is as follows:
Full version Smoothed version
The triphthong [aʊə] is often pronounced just as /ɑː/, especially in some words like the possessive our. Notice how clearly this happens in the following examples:
Actually, this is the way our is currently said in British English (and very often in American English too, although in AE the final r is pronounced). Producing the full triphthong [aʊə] in the word our sounds a bit unnatural in different varieties of English.
It is also interesting to note that the smoothing of triphtongs bring about some new homophones. Both [aʊə] and [aɪə] might be produced as [aə], so the words tower and tyre are pronounced [taə], which can be confusing if you’re not aware of this process.
Another good example of smoothing is the word mayor, which is always pronounced /meə/ in British English ([meɪər] in American English). Admittedly, in this case the British version is much more difficult to understand than the American for non native speakers.
Here are some sentences which include the three cases studied above:
Two special cases. The triphthongs [əʊə] and [ɔɪə] need some further explanation, so I’ll treat them separately.
1. The distinguishing fact about the smoothed version of [əʊə] is that it is realized as a monophthong, the sound /ɜː/. This is only natural if you think that, by taking out the [ʊ] in the middle, you get two schwas together [əə], which is the same as /ɜː/ (for the relation between /ə/ and /ɜː/, see here).
Let’s listen to the difference:
And here you have it in context:
2. The smoothing of the triphthong [ɔɪə] is more controversial, and some authors don’t include it in the catalogue of triphthongs subject to this process. So, we can safely assume that it happens less often. Nevertheless, it does happen sometimes (and we have a good example by none other than Ben Kingsley below), so we’ll treat it here as well.
This is how it sounds:
And this is a contextualized example:
And here is sir Ben Kingsley:
A useful thing to remember is that smoothing doesn’t necessarily erase the [ɪ] or [ʊ] in the middle of the triphthong completely. In some cases, those vowels are heard in a very faint, debilitated form, to the extent that it might be difficult to say if they are pronounced at all or not.
Now, let’s listen to a few more examples taken from real life: