Hi Guy. Today we will learn about diphthong. Below is a video about diphthong. Let's see what the diphthong is

A diphthong also known as a gliding vowel, is a combination of two adjacent vowel sounds within the same syllable. Technically, a diphthong is a vowel with two different targets: that is, the tongue (and/or other parts of the speech apparatus) moves during the pronunciation of the vowel. In many dialects of English, the phrase no highway cowboys has five distinct diphthongs, one in every syllable.

Diphthongs contrast with monophthongs, where the tongue or other speech organs do not move and the syllable contains only a single vowel sound. For instance, in English, the word ah is spoken as a monophthong (/ɑː/), while the word ow is spoken as a diphthong in most dialects (/aʊ/). Where two adjacent vowel sounds occur in different syllables—for example, in the English word re-elect—the result is described as hiatus, not as a diphthong.

Diphthongs often form when separate vowels are run together in rapid speech during a conversation. However, there are also unitary diphthongs, as in the English examples above, which are heard by listeners as single-vowel sounds (phonemes).

Diphthongs use two vowel sounds in one syllable to make a speech sound.

Falling and rising

Falling (or descending) diphthongs start with a vowel quality of higher prominence (higher pitch or volume) and end in a semivowel with less prominence, like [aɪ̯] in eye, while rising (or ascending) diphthongs begin with a less prominent semivowel and end with a more prominent full vowel, similar to the [ja] in yard. (Note that "falling" and "rising" in this context do not refer to vowel height; for that, the terms "opening" and "closing" are used instead. See below.) The less prominent component in the diphthong may also be transcribed as an approximant, thus [aj] in eye and [ja] in yard. However, when the diphthong is analysed as a single phoneme, both elements are often transcribed with vowel letters (/aɪ̯/, /ɪ̯a/). Note also that semivowels and approximants are not equivalent in all treatments, and in the English and Italian languages, among others, many phoneticians do not consider rising combinations to be diphthongs, but rather sequences of approximant and vowel. There are many languages (such as Romanian) that contrast one or more rising diphthongs with similar sequences of a glide and a vowel in their phonetic inventory (see semivowel for examples).

Closing, opening, and centering

Vowel diagram illustrating closing diphthongs of Belgian Standard Dutch, from Verhoeven

Vowel diagram illustrating centering diphthongs of the Dutch dialect of Orsmaal-Gussenhoven, from Peters 

In closing diphthongs, the second element is more close than the first (e.g. [ai]); in opening diphthongs, the second element is more open (e.g. [ia]). Closing diphthongs tend to be falling ([ai̯]), and opening diphthongs are generally rising ([i̯a]),[10] as open vowels are more sonorous and therefore tend to be more prominent. However, exceptions to this rule are not rare in the world's languages. In Finnish, for instance, the opening diphthongs /ie̯/ and /uo̯/ are true falling diphthongs, since they begin louder and with higher pitch and fall in prominence during the diphthong.

A third, rare type of diphthong that is neither opening nor closing is height-harmonic diphthongs, with both elements at the same vowel height. These occurred in Old English:

beon [beo̯n] "be"

ceald [kæɑ̯ld] "cold"

A centering diphthong is one that begins with a more peripheral vowel and ends with a more central one, such as [ɪə̯], [ɛə̯], and [ʊə̯] in Received Pronunciation or [iə̯] and [uə̯] in Irish. Many centering diphthongs are also opening diphthongs ([iə̯], [uə̯]).

Diphthongs may contrast in how far they open or close. For example, Samoan contrasts low-to-mid with low-to-high diphthongs:

’ai [ʔai̯] 'probably'

’ae [ʔae̯] 'but'

’auro [ʔau̯ɾo] 'gold'

ao [ao̯] 'a cloud'

Narrow and wide

Narrow diphthongs are the ones that end with a vowel which on a vowel chart is quite close to the one that begins the diphthong, for example Northern Dutch [eɪ], [øʏ] and [oʊ]. Wide diphthongs are the opposite - they require a greater tongue movement, and their offsets are farther away from their starting points on the vowel chart. Examples of wide diphthongs are RP/GA English [aɪ] and [aʊ].

Length

Languages differ in the length of diphthongs, measured in terms of morae. In languages with phonemically short and long vowels, diphthongs typically behave like long vowels, and are pronounced with a similar length.[12][citation needed] In languages with only one phonemic length for pure vowels, however, diphthongs may behave like pure vowels.[citation needed] For example, in Icelandic, both monophthongs and diphthongs are pronounced long before single consonants and short before most consonant clusters.

Some languages contrast short and long diphthongs. In some languages, such as Old English, these behave like short and long vowels, occupying one and two morae, respectively. Languages that contrast three quantities in diphthongs are extremely rare, but not unheard of; Northern Sami is known to contrast long, short and "finally stressed" diphthongs, the last of which are distinguished by a long second element.