Phonology Consonants

When consonants appear in pairs, fortis consonants (i.e. aspirated or voiceless) appear on the left and lenis consonants (i.e. lightly voiced or voiced) appear on the right

Consonant phonemes of Received Pronunciation^[8]
	Bilabial	Labio- dental	Dental	Alveolar	Post- alveolar	Palatal	Velar	Glottal
Nasal^1	m			n			ŋ
Plosive	p  b			t  d			k  g
Affricate					tʃ  dʒ
Fricative		f  v	θ  ð^2	s  z	ʃ  ʒ			h^3
Approximant				ɹ^1, 4		j	w
Lateral				l^1, 5

1. Nasals and liquids may be syllabic in unstressed syllables.

2. /ð/ is more often a weak dental plosive; the sequence /nð/ is often realized as [n̪n̪].

3. /h/ becomes [ɦ] between voiced sounds.

4. /ɹ/ is postalveolar unless devoicing results in a voiceless fricative articulation (see below).

5. /l/ is velarized in the syllable coda.

Unless preceded by /s/, fortis plosives (/p/, /t/, and /k/) are aspirated before stressed vowels; when a sonorant /l/, /ɹ/, /w/, or /j/ follows, this aspiration is indicated by partial devoicing of the sonorant.^[9]

Syllable final /p/, /t/, /tʃ/, and /k/ are preceded by a glottal stop (see Glottal reinforcement); /t/ may be fully replaced by a glottal stop, especially before a syllabic nasal (button [bɐʔn̩]).^[10][11]

Vowels

Monophthongs
	Front		Central		Back
	long	short	long	short	long	short
Close	iː	ɪ			uː	ʊ
Mid		e	ɜː	ə	ɔː
Open		æ		ʌ	ɑː	ɒ

Examples of short vowels: /ɪ/ in kit and mirror, /ʊ/ in put, /e/ in dress and merry, /ʌ/ in strut and curry, /æ/ in trap and marry, /ɒ/ in lot and orange, /ə/ in ago and sofa.

Examples of long vowels: /iː/ in fleece, /uː/ in goose, /ɜː/ in nurse, /ɔː/ in north and thought, /ɑː/ in father and start.

RP's long vowels are slightly diphthongised. Especially the high vowels /iː/ and /uː/ which are often narrowly transcribed in phonetic literature as diphthongs [ɪi] and [ʊu].^{[citation needed]}

"Long" and "short" are relative to each other. Because of phonological process affecting vowel length, short vowels in one context can be longer than long vowels in another context.^[12] For example, a long vowel following a fortis consonant sound (/p/, /k/, /s/, etc.) is shorter; reed is thus pronounced [ɹiːd̥] while heat is [hiʔt].^{[citation needed]}

Conversely, the short vowel /æ/ becomes longer if it is followed by a lenis consonant. Thus, bat is pronounced [b̥æʔt] and bad is [b̥æːd̥]. In natural speech, the plosives /t/ and /d/ may be unreleased utterance-finally, thus distinction between these words would rest mostly on vowel length.^[11]

In addition to such length distinctions, unstressed vowels are both shorter and more centralized than stressed ones. In unstressed syllables occurring before vowels and in final position, contrasts between long and short high vowels are neutralized and short [i] and [u] occur.^[13]

Diphthong	Example
Closing
/eɪ/	/beɪ/	bay
/aɪ/	/baɪ/	buy
/ɔɪ/	/bɔɪ/	boy
/əʊ/	/bəʊ/	beau
/aʊ/	/bɹaʊz/	browse
Centring
/ɪə/	/bɪə/	beer
/eə/	/beə/	bear
/ʊə/	/bʊə/	boor

Before World War II, /ɔə/ appeared in words like door but this has largely disappeared, having merged with /ɔː/; /ʊə/ is also beginning to merge with /ɔː/.^[14] In the closing diphthongs, the glide is often so small as to be undetectable so that day and dare can be narrowly transcribed as [d̥e̞ː] and [d̥ɛː] respectively.^[15]

RP also possesses the triphthongs /aɪə/ as in ire and /aʊə/ as in hour. The realizations sketched in the following table are not phonemically distinctive, though the difference between /aʊə/, /aɪə/, and /ɑː/ may be neutralised to become [ɑː] or [äː].

Triphthongs^[11]
As two syllables	Triphthong	Loss of mid-element	Further simplified as
[aɪ.ə]	[aɪə]	[aːə]	[aː]
[ɑʊ.ə]	[ɑʊə]	[ɑːə]	[ɑː]

Not all reference sources use the same system of transcription. In particular:^{[citation needed]}

• /æ/ as in trap is often written /a/.

• /e/ as in dress is sometimes written /ɛ/.^[16]

• /ɜː/ as in nurse is sometimes written /əː/.

• /aɪ/ as in price is sometimes written /ʌɪ/.

• /aʊ/ as in mouse is sometimes written /ɑʊ/

• /eə/ as in square is sometimes written /ɛə/, and is also sometimes treated as a long monophthong /ɛː/.

Most of these variants are used in the transcription devised by Clive Upton for the Shorter Oxford English Dictionary (1993) and now used in many other Oxford University Press dictionaries.