he word diphthong comes from the Latin diphthongus, a word that at the same time has its origin in a word derived from Greek language. The term refers to the union or the combination of a pair of adjacent vowels that are expressed in the same syllable. It is a vowel that has two different targets.
The diphthong is a type of sound chain that is formed by the articulation of two adjacent vowels followed by each other without any interruption, generating a smooth transition that characterizes the timbres of each vowels.
The diphthong is the union that occurs between two different vowels that are placed continuously within the same syllable and may be formed by an open vowel such as e, e, o, and a closed vowel such as i and u. The process by which one vowel sound moved to another is known as gliding, this is the reason why a diphthong is also called “gliding vowel”. Another types of names to refer to this type of sound are compound vowels, complex or moving vowels. It is important to mention that the sound change that converts a single vowel into a diphthong is known as diphthongization.
In English language, a diphthong is a one-syllable sound formed of two vowels. In English pronunciation there are eight different diphthong sounds. For example:
The sound /ei/ in play has two vowel sounds, /e/ and /i/.
Maybe the most important aspect when we refer to diphthongs in English is that they are not formed by two simple vowels together, but one long vowel where the pronunciation changes since the beginning to the end, in other words, the pronunciation changes completely at the end of the word. The most common diphthongs in English, specially USA, are said to be /ow/, /ou/, /oy/ and /oi/ as in bow, ground, toy and coin.
Their main characteristics are the following:
There are two different types of diphthong, and these can be:
It is important to mention that diphthongs [aɪ], [eɪ], [ɔɪ], and [aʊ] can be found in British and American English, and [əʊ] only in British.
The most common types of diphthongs that you can find in American English are the following:
This type of diphthong is very similar to the long A sound. The correct way to pronounce it is as a long A sound sliding into a long E sound. It is important to understand that some dialects pronounce the long A sound as one single sound. There is also the case where is pronounce as two vowel sounds. Some people who has a southern accent, mainly from the south part of the United States will stretch out the diphthong more. Some examples are:
The sound of this diphthong can vary from one dialect to another one. In some places the long I sound is pronounced in the words as one single sound. Some dialects pronounce the vowel sound more like the “AH” sound you would here in “ball”. Or it can also be pronounced as two vowel sounds. Some examples of words with this type of diphthong are:
Briceño V., Gabriela. (2019). Diphthong. Recovered on 17 September, 2021, de Euston96: https://www.euston96.com/en/diphthong/