Editing Diphthong (section)

==Types==

===Falling and rising===
'''Falling''' (or '''descending''') diphthongs start with a vowel quality of higher [[prominence (phonetics)|prominence]] (higher pitch or volume) and end in a semivowel with less prominence, like {{IPA|[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 {{IPA|[ja]}} in ''yard''. (Sometimes, however, the terms "falling" and "rising" are used, instead, to refer to [[vowel height]], i.e. as synonyms of the terms "closing" and "opening".<ref>{{cite book|last=Bussmann|first=Hadumod|year=2006|title=Routledge Dictionary of Language and Linguistics|translator-first1=Gregory|translator-last1=Trauth|translator-first2=Kerstin|translator-last2=Kassazi|chapter=Diphthong|url={{GBurl|id=O0-9Iw0Qh6EC|p=316}}|location=London/New York|publisher=Routledge|page=316|isbn=0-203-98005-0|access-date=24 March 2023}}</ref> See below.) The less prominent component in the diphthong may also be transcribed as an [[approximant]], thus {{IPA|[aj]}} in ''eye'' and {{IPA|[ja]}} in ''yard''. However, when the diphthong is analysed as a single [[phoneme]], both elements are often transcribed with vowel symbols ({{IPA|/aɪ̯/}}, {{IPA|/ɪ̯a/}}). Semivowels and approximants are not equivalent in all treatments, and in the [[English (language)|English]] and [[Italian (language)|Italian]] languages, among others, many [[phonetician]]s do not consider rising combinations to be diphthongs, but rather sequences of approximant and vowel. There are many languages (such as [[#Romanian|Romanian]]) that contrast one or more rising diphthongs with similar sequences of a glide and a vowel in their phonetic inventory<ref name="Chiorana">{{Harvcoltxt|Chițoran|2002a|p=203}}</ref> (see [[semivowel]] for examples).

===Closing, opening, and centering===
[[File:Belgian Dutch diphthongs chart.svg|thumb|upright=1.15|[[Vowel diagram]] illustrating closing diphthongs of Belgian Standard [[Dutch language|Dutch]], from {{Harvcoltxt|Verhoeven|2005|p=245}}]]
[[File:Orsmaal-Gussenhoven Dutch centering diphthongs chart.svg|thumb|upright=1.15|Vowel diagram illustrating centering diphthongs of the [[Dutch language|Dutch]] dialect of [[Orsmaal-Gussenhoven dialect|Orsmaal-Gussenhoven]], from {{Harvcoltxt|Peters|2010|p=241}}]]
In '''closing''' diphthongs, the second element is more [[close vowel|close]] than the first (e.g. {{IPA|[ai]}}); in '''opening''' diphthongs, the second element is more [[open vowel|open]] (e.g. {{IPA|[ia]}}). Closing diphthongs tend to be falling ({{IPA|[ai̯]}}), and opening diphthongs are generally rising ({{IPA|[i̯a]}}),<ref>{{Cite book|title=Dictionary of Linguistics and Phonetics|editor-last=Crystal|editor-first=David|location=Malden, MA|publisher=Blackwell|year=2008|chapter=diphthong|edition=6|isbn=978-1-4051-5297-6|url={{GBurl|id=6muoEAAAQBAJ|p=146}}|access-date=24 March 2023}}</ref> as open vowels are more [[sonorant|sonorous]] and therefore tend to be more prominent. However, exceptions to this rule are not rare in the world's languages. In [[Finnish phonology|Finnish]], for instance, the opening diphthongs {{IPA|/ie̯/}} and {{IPA|/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.<ref>{{cite book|editor-first1=Richard M.|editor-last1=Hogg|editor-first2=Norman Francis|editor-last2=Blake|editor-link2=Norman Blake (academic)|editor-first3=Robert William|editor-last3=Burchfield|title=The Cambridge History of the English Language|location=Cambridge|publisher=Cambridge University Press|year=1992|volume=1|page=49|isbn=0-521-26475-8|url={{GBurl|id=UlD3ksfXl5IC|p=49}}|access-date=24 March 2023}}</ref> These may have occurred in [[Old English]]:
* ''beorht'' {{IPA|[beo̯rxt]}} "bright"
* ''ċeald'' {{IPA|[t͡ʃæɑ̯ld]}} "cold"

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

Diphthongs may contrast in how far they open or close. For example, [[Samoan language|Samoan]] contrasts low-to-mid with low-to-high diphthongs:
* '''ai'' {{IPA|[ʔai̯]}} 'probably'
* '''ae'' {{IPA|[ʔae̯]}} 'but'
* '''auro'' {{IPA|[ʔau̯ɾo]}} 'gold'
* ''ao'' {{IPA|[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 {{IPA|[eɪ]}}, {{IPA|[øʏ]}} and {{IPA|[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 {{IPA|[aɪ]}} and {{IPA|[aʊ]}}.

===Length===
Languages differ in the length of diphthongs, measured in terms of [[Mora (linguistics)|morae]]. In languages with phonemically short and long vowels, diphthongs typically behave like long vowels, and are pronounced with a similar length.<ref>{{Cite journal |last=Anderson |first=Catherine |date=2018-03-15 |title=2.8 Diphthongs |url=https://pressbooks.pub/essentialsoflinguistics/chapter/2-8-diphthongs/ |journal=Pressbooks |language=en |via=Pressbooks}}</ref> In languages with only one phonemic length for pure vowels, however, diphthongs may behave like pure vowels.<ref>{{Cite journal |last=Paschen |first=Ludger |last2=Fuchs |first2=Susanne |last3=Seifart |first3=Frank |date=September 2022 |title=Final Lengthening and vowel length in 25 languages |url=https://linkinghub.elsevier.com/retrieve/pii/S0095447022000547 |journal=Journal of Phonetics |language=en |volume=94 |pages=101179 |doi=10.1016/j.wocn.2022.101179|doi-access=free }}</ref> For example, in [[Icelandic language|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 [[Mora (linguistics)|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 longer second element.<ref name="Aikio 2022">{{Cite book |last=Aikio |first=Ante |title=The Oxford Guide to the Uralic Languages |last2=Ylikoski |first2=Jussi |date=2022 |publisher=Oxford University Press |isbn=9780191821516 |editor-last=Bakró-Nagy |editor-first=Marianne |pages=147–177 |chapter=North Saami |doi=10.1093/oso/9780198767664.003.0010 |editor-last2=Laakso |editor-first2=Johanna |editor-last3=Skribnik |editor-first3=Elena}}</ref>{{rp|149}}