Diphthong is the name given to the combination of a vowel sound and a semivocal sound emitted in a single effort of voice. The diphthong differs from the hiatus in that the latter consists of two vowels and is not pronounced in the same syllable. [ 1 ]
When the vowel precedes the semivowel it is called decreasing diphthong . In the Portuguese language we have the following decreasing diphthongs.
- l eite / ˈl ej .ti / ( PB ) / ˈl ɐj .tɨ / ( PE )
- c ai/ ajc aj /
- d ói/ ˈd ɔj /
- f oi/ ˈf oj /
- c uidata / c uj .ˈda.du /
- v iu/ ˈv iw /
- m eu/ em ew /
- c éu/ ˈc ɛw /
- m au/ awm aw /
- s or/ ˈs ow / (in many dialects it is not pronounced as diphthong, but as a vowel: / ˈs o /)
In many Brazilian dialects, due to the phonation of the phoneme / l / at the end of a syllable, the following cases are also considered to be decreasing diphthongs. Ex.:
- fun il/fu.ˈn iw /
- f eltro / f ew .tɾu /
- m el/ ˈm ɛw /
- m al/ awm aw /
- S ol/ ɔw /
- s olgiven I / O w .da.du /
- az ul/ aˈz uw /
Diphthongs can be called nasal diphthongs if the vowel they contain is a nasal vowel.
- m ae/ m ɐj /
- p ns/ w OJ /
- n will be/ n ɐw /
When the semivowel precedes the vowel it is called increasing diphthong . According to the conventions of the Portuguese language only diphthongs are considered stable diphthongs whose first element is the semivowel / w /, and when they are preceded by the sounds / k / or / ɡ /. Ex.:
- ag uardar / aɡ wa ʀˈdaʀ / (PB) / ɐɡ wɐ ɾˈdaɾ / (PE)
- ig ual / iˈɡ wa w / (PB) / iˈɡ wa l /
- Q waterup / k wa zi / (PB) / k wa zɨ / (EP)
- q waternt / k wa tu /
The other cases that in writing are usually represented by «i» + vowel or «u» plus vowel (or, in European Portuguese, «e» + vowel or «o» + vowel), are usually considered as hiatuses .
In the case of diphthongs formed by u + i preceded by g or q, writing does not make it possible to know whether it is a growing diphthong or a decreasing diphthong, and there may be ambiguity. For example, the 3rd person of the present tense of the verb arguir, (he) argui (formerly written argüi , with decreasing diphthong), is written in the same way as the 1st person of the past tense, (eu) argui (formerly argüi , with increasing diphthong) . This last form can only take an accent ( arguí ) if, instead of diphthong, there is a gap between U and I, because the orthographic rules establish that in these cases the I only takes accent if it does not form diphthong with the previous vowel. So Switzerlandit has an accent (U and I do not form diphthong, but hiatus), but sausage does not (since U and I form diphthong).
Note: qu “in: it is not a vowel encounter , as the U is not pronounced. Therefore, it is a digraph and not a diphthong.
Diphthongs can also be classified as open and closed *
Diphthongs are open when constituted by open vowels, and closed, by closed or nasal vowels.
As for the timbre, the vowels can be: open , closed and reduced .
The timbre is the result of the position of the tongue in the oral cavity at the moment of the emission of sounds:
- with the tongue in the low position, the open timbrevowels are produced : [a, é, ó];
- with the elevation of the tongue, the closed timbrevowels are produced : [ê, ô, i, u];
- in the reduced ones, the timbre is almost canceled. In Portuguese, they are considered semi-vowels [ iand u ].
Diphthong is the meeting of two tones: a vowel and a semi-vowel:
- Open diphthongIt is said that the diphthong is opened when a vowel of open timbre is joined to a semivowel or vice versa:
- Closed diphthong When a closed timbre vowel is joined to a semi-vowel, it is said that there is a closed diphthong: (oral): (nasal):