Editing Received Pronunciation (section)

====Diphthongs and triphthongs====
[[Image:RP English diphthongs chart.svg|thumb|Diphthongs of RP. From {{harvtxt|Roach|2004|p=242}}]]
[[Image:cruttenden_closing_diphthongs.svg|thumb|Closing diphthongs of RP (with the diphthongal realisations of {{IPA|/iː/}} and {{IPA|/uː/}}). Adapted from {{harvtxt|Cruttenden| 2014|}}]]
[[Image:cruttenden_centring_diphthongs.svg|thumb|Centring diphthongs of RP. Adapted from {{harvtxt|Cruttenden| 2014|}}]]
{| class="wikitable" style="text-align: center;"
|-
! [[Diphthong]]
! colspan="2" |Example
|-
! colspan="3" | Closing
|-
| {{IPA|/eɪ/}} {{Audio|en-uk-a.ogg||help=no}} || {{IPA|/beɪ/}} || bay
|-
| {{IPA|/aɪ/}} {{Audio|en-uk-I.ogg||help=no}} || {{IPA|/baɪ/}} || buy
|-
| {{IPA|/ɔɪ/}} {{Audio|en-uk-oi.ogg||help=no}} || {{IPA|/bɔɪ/}} || boy
|-
| {{IPA|/əʊ/}} {{Audio|En-uk-oh.ogg||help=no}} || {{IPA|/bəʊ/}} || beau
|-
| {{IPA|/aʊ/}} || {{IPA|/baʊ/}} || bough
|-
! colspan="3" | Centring
|-
| {{IPA|/ɪə/}} {{Audio|en-uk-ear.ogg||help=no}} || {{IPA|/bɪə/}} || beer
|-
| {{IPA|/ʊə/}} || {{IPA|/bʊə/}} || boor
|}

The centring diphthongs are gradually being eliminated in RP. The vowel {{IPA|/ɔə/}} (as in ''door'', ''boar'') had largely merged with {{IPA|/ɔː/}} by the Second World War, and the vowel {{IPA|/ʊə/}} (as in ''poor'', ''tour'') has more recently merged with {{IPA|/ɔː/}} as well among most speakers,{{sfnp|Roca|Johnson|1999|p=200}} although the sound {{IPA|/ʊə/}} is still found in conservative speakers, and in less common words such as ''boor''. See [[Cure–force merger|{{sc2|CURE}}–{{sc2|FORCE}} merger]]. More recently {{IPA|/ɛə/}} has become a pure long vowel {{IPA|/ɛː/}}, as explained above. {{IPA|/ɪə/}} is increasingly pronounced as a monophthong {{IPA|[ɪː]}}, although without merging with any existing vowels.{{sfnp|Cruttenden|2014|p=154}}

The diphthong {{IPA|/əʊ/}} is pronounced by some RP speakers in a noticeably different way when it occurs before {{IPA|/l/}}, if that consonant is [[Syllable final|syllable-final]] and not followed by a vowel (the context in which {{IPA|/l/}} is pronounced as a "dark l"). The realisation of {{IPA|/əʊ/}} in this case begins with a more back, rounded and sometimes more open vowel quality; it may be transcribed as {{IPA|[ɔʊ]}} or {{IPA|[ɒʊ]}}. It is likely that the backness of the diphthong onset is the result of [[Allophone|allophonic]] variation caused by the raising of the back of the tongue for the {{IPA|/l/}}. If the speaker has "l-vocalization" the {{IPA|/l/}} is realised as a back rounded vowel, which again is likely to cause backing and rounding in a preceding vowel as [[coarticulation]] effects. This phenomenon has been discussed in several blogs by [[John C. Wells]].<ref>{{cite web |last=Wells |first=John |title=Blog July 2006 |url=http://www.phon.ucl.ac.uk/home/wells/blog0607.htm |access-date=24 March 2014}}</ref><ref>{{cite web |last=Wells |first=John |title=Blog July 2009 |url=http://www.phonetic-blog.blogspot.fr/2009_10_01_archive.html |access-date=24 March 2014}}</ref><ref>{{cite web |last=Wells |first=John |title=Blog Nov 2009 |url=http://www.phonetic-blog.blogspot.fr/2009_11_01_archive.html |access-date=24 March 2014}}</ref> In the recording included in this article the phrase "fold his cloak" contains examples of the {{IPA|/əʊ/}} diphthong in the two different contexts. The onset of the pre-{{IPA|/l/}} diphthong in "fold" is slightly more back and rounded than that in "cloak".

RP also possesses the [[triphthong]]s {{IPA|/aɪə/}} as in ''tire'', {{IPA|/aʊə/}} as in ''tower'', {{IPA|/əʊə/}} as in ''lower'', {{IPA|/eɪə/}} as in ''layer'' and {{IPA|/ɔɪə/}} as in ''loyal''. There are different possible realisations of these items: in slow, careful speech they may be pronounced as two syllables with three distinct vowel qualities in succession, or as a monosyllabic triphthong. In more casual speech the middle vowel may be considerably reduced, by a process known as [[smoothing (phonetics)|smoothing]], and in an extreme form of this process the triphthong may even be reduced to a single long vowel.{{sfnp|Roach|2009|pp=18–19}} In such a case the difference between {{IPA|/aʊə/}}, {{IPA|/aɪə/}}, and {{IPA|/ɑː/}} in ''tower'', ''tire'', and ''tar'' may be [[Archiphoneme|neutralised]] with all three units realised as {{IPA|[ɑː]}} or {{IPA|[äː]}}. This type of smoothing is known as the [[English-language vowel changes before historic /r/#Tower–tire, tower–tar and tire–tar mergers|''tower''–''tire'', ''tower''–''tar'' and ''tire''–''tar'' mergers]].

{| class="wikitable" style="text-align: center;"
|+ [[Triphthong]]s{{sfnp|Gimson|1970}}
! As two syllables
! Triphthong
! Loss of mid-element
! Further simplified as
! Example
|-
| {{IPA|[aɪ.ə]}}
| {{IPA|[aɪə]}}
| {{IPA|[aːə]}}
| {{IPA|[aː]}}
| tire
|-
| {{IPA|[ɑʊ.ə]}}
| {{IPA|[ɑʊə]}}
| {{IPA|[ɑːə]}}
| {{IPA|[ɑː]}}
| tower
|-
| {{IPA|[əʊ.ə]}}
| {{IPA|[əʊə]}}
| {{IPA|[əːə]}}
| {{IPA|[ɜː]}}
| lower
|-
| {{IPA|[eɪ.ə]}}
| {{IPA|[eɪə]}}
| {{IPA|[ɛːə]}}
| {{IPA|[ɛː]}}
| layer
|-
| {{IPA|[ɔɪ.ə]}}
| {{IPA|[ɔɪə]}}
| {{IPA|[ɔːə]}}
| {{IPA|[ɔː]}}
| loyal
|}