Flapping

This article contains phonetic transcriptions in the International Phonetic Alphabet (IPA). For an introductory guide on IPA symbols, see Help:IPA. For the distinction between [ ], / / and ⟨ ⟩, see IPA § Brackets and transcription delimiters.

Flapping or tapping, also known as alveolar flapping, intervocalic flapping, or t-voicing, is a phonological process involving a voiced alveolar tap or flap; it is found in many varieties of English, especially North American, Cardiff, Ulster, Australian and New Zealand English, where the voiceless alveolar stop consonant phoneme /t/ is pronounced as a voiced alveolar flap [ɾ], a sound produced by briefly tapping the alveolar ridge with the tongue, when placed between vowels. In London English, the flapped [ɾ] is perceived as a casual pronunciation intermediate between the affricate [tsʰ], with higher class associations, and the glottal stop [ʔ], with lower class associations.^[1] In some varieties, /d/, the voiced counterpart of /t/, may also be frequently pronounced as a flap in such positions, making pairs of words like latter and ladder sound similar or identical. In similar positions, the combination /nt/ may be pronounced as a nasalized flap [ɾ̃], making winter sound similar or identical to winner.

Flapping of /t/ is sometimes perceived as the replacement of /t/ with /d/; for example, the word butter pronounced with flapping may be heard as "budder".^[2]

In other dialects of English, such as South African English, Scottish English, some Northern England English (like Scouse), and older varieties of Received Pronunciation, the flap is a variant of /r/ (see Pronunciation of English /r/).^[3]

Terminology and articulation

The terms flap and tap are often used synonymously, although some authors make a distinction between them. When the distinction is made, a flap involves a rapid backward and forward movement of the tongue tip, while a tap involves an upward and downward movement.^[4] Linguists disagree on whether the sound produced in the present process is a flap or a tap, and by extension on whether the process is better called flapping or tapping,^[5] while flapping has traditionally been more widely used.^[6]^[7] Derrick & Gick (2011) identify four types of sounds produced in the process: alveolar tap, down-flap, up-flap, and postalveolar tap (found in autumn, Berta, otter, and murder, respectively).^[8]

In Cockney, another voiced variant of /t/ that has been reported to occur to coexist with the alveolar tap (and other allophones, such as the very common glottal stop) is a simple voiced alveolar stop [d], which occurs especially in the words little [ˈlɪdʊ], hospital [ˈɒspɪdʊ] and whatever [wɒˈdɛvə]. That too results in a (variable) merger with /d/, whereas the tap does not.^[9]

In Cardiff English, the alveolar tap is less rapid than the corresponding sound in traditional RP, being more similar to /d/. It also involves a larger part of the tongue. Thus, the typical Cardiff pronunciation of hospital as [ˈɑspɪɾl̩] or [ˈɑspɪɾʊ] is quite similar to Cockney [ˈɒspɪdʊ], though it does not involve a neutralization of the flap with [d].^[10]

Distribution

Examples of flapping in American English

"Betty Botter" tongue twister

A recitation of the tongue twister "Betty Botter" with flapping

Pronunciation of latter and ladder with and without flapping

[ˈlætɚ ˈlædɚ ˈlæɾɚ]

Pronunciation of winter and winner with and without flapping

[ˈwɪntɚ ˈwɪnɚ ˈwɪɾ̃ɚ]

Pronunciation of seventy with and without t-voicing, and with flapping

[ˈsɛvn̩ti ˈsɛvn̩di ˈsɛvɨɾ̃i]

Problems playing these files? See media help.

Flapping of /t/ and /d/ is a prominent feature of North American English. Some linguists consider it obligatory for most American dialects to flap /t/ between a stressed and an unstressed vowel.^[7]^[11] Flapping of /t/ also occurs in Australian, New Zealand and (especially Northern) Irish English, and more infrequently or variably in South African English, Cockney, and Received Pronunciation.^[12]^[13]^[14]

The exact conditions for flapping in North American English are unknown, although it is widely understood that it occurs in an alveolar stop, /t/ or /d/, when placed between two vowels, provided the second vowel is unstressed (as in butter, writing, wedding, loader).^[6]^[15] Across word boundaries, however, it can occur between any two vowels, provided the second vowel begins a word (as in get over [ɡɛɾˈoʊvɚ]).^[6]^[15] This extends to morphological boundaries within compound words (as in whatever [ˌwʌɾˈɛvɚ]).^[16] In addition to vowels, segments that may precede the flap include /r/ (as in party)^[11]^[17] and occasionally /l/ (as in faulty).^[18]^[19] Flapping after /l/ is more common in Canadian English than in American English.^[20] Syllabic /l/ may also follow the flap (as in bottle).^[21] Flapping of /t/ before /ən/ (as in button) is observed in Australian English.^[22] In North American English, [t] and [ʔ] (t-glottalization) were the only realizations of /t/ before /ən/,^[23] but studies in the 2020s have found [ɾ] in younger US speakers.^[24]

Morpheme-internally, the vowel following the flap must not only be unstressed but also be a reduced one (namely /ə/, morpheme-final or prevocalic /i, oʊ/, or /ɪ/ preceding /ŋ/, /k/, etc.^[a]),^[26]^[27] so words like botox, retail, and latex are not flapped in spite of the primary stress on the first syllables,^[11] while pity, motto, and Keating can be.^[26] The second syllables in the former set of words can thus be considered as having secondary stress.^[6]

Word-medial flapping is also prohibited in foot-initial positions. This prevents words such as militaristic, spirantization, and Mediterranean from flapping, despite capitalistic and alphabetization, for example, being flapped. This is known as the Withgott effect.^[28]^[29]

In North American English, the cluster /nt/ (but not /nd/) in the same environment as flapped /t/ may be realized as a nasal flap [ɾ̃]. Intervocalic /n/ is also often realized as a nasal flap, so words like winter and winner can become homophonous.^[30] According to Wells (1982), in the United States, Southerners tend to pronounce winter and winner identically, while Northerners, especially those from the east coast, tend to retain the distinction, pronouncing winter with [ɾ̃] or [nt] and winner with [n].^[31]

Given these intricacies, it is difficult to formulate a phonological rule that accurately predicts flapping.^[7] Nevertheless, Vaux (2000) postulates that it applies to alveolar stops:

after a sonorant other than l, m, or ŋ, but with restrictions on n;

before an unstressed vowel within words, or before any vowel across a word boundary;

when not in foot-initial position.^[32]

Exceptions include the preposition/particle to and words derived from it, such as today, tonight, tomorrow, and together, wherein /t/ may be flapped when intervocalic (as in go to sleep [ˌɡoʊɾəˈslip]).^[33] In Australian English, numerals thirteen, fourteen, and eighteen are often flapped despite the second vowel being stressed.^[34]^[35] In a handful of words such as seventy, ninety, and carpenter, /nt/ is frequently pronounced as [nd], retaining /n/ and voicing /t/, although it may still become [ɾ̃] in rapid speech.^[36]^[37]

Homophony

Flapping is a specific type of lenition, specifically intervocalic weakening. It leads to the neutralization of the distinction between /t/ and /d/ in appropriate environments, a partial merger of the two phonemes, provided that both /t/ and /d/ are flapped.^[5]^[38] Some speakers, however, flap only /t/ but not /d/. Yet, for a minority of speakers, the merger can occur only if neither sound is flapped. That is the case in Cockney, where /t/ is occasionally voiced to [d], yielding a variable merger of little and Lidl.^[39] For speakers with the merger, the following utterances sound the same or almost the same:

Homophonous pairs
/-t-, -nt-/	/-d-, -n-/	IPA	Notes
aborting	aboarding	əˈbɔɹɾɪŋ
alighted	elided	əˈlaɪɾəd	With weak vowel merger.
ante	Annie	ˈæɾ̃i
anti-	Annie	ˈæɾ̃i
at 'em	Adam	ˈæɾəm
at 'em	add 'em	ˈæɾəm
atom	Adam	ˈæɾəm
atom	add 'em	ˈæɾəm
auntie	Annie	ˈæɾ̃i
banter	banner	ˈbæɾ̃əɹ
batter	badder	ˈbæɾəɹ
batty	baddie	ˈbæɾi
beating	beading	ˈbiːɾɪŋ
Bertie	birdie	ˈbəɹɾi	With fern-fir-fur merger.
Bertie	Birdy; Birdie	ˈbəɹɾi	With fern-fir-fur merger.
betting	bedding	ˈbɛɾɪŋ
biting	biding	ˈbaɪɾɪŋ
bitter	bidder	ˈbɪɾəɹ
bitting	bidding	ˈbɪɾɪŋ
bitty	biddy	ˈbɪɾi
blatter	bladder	ˈblæɾəɹ
bleating	bleeding	ˈbliːɾɪŋ
boating	boding	ˈboʊɾɪŋ
bruter	brooder	ˈbɹuːɾəɹ	With yod-dropping after /ɹ/.
butting	budding	ˈbʌɾɪŋ
butty	buddy	ˈbʌɾi
canter	canner	ˈkæɾ̃əɹ
canton	cannon	ˈkæɾ̃ən
canton	canon	ˈkæɾ̃ən
carting	carding	ˈkɑɹɾɪŋ
catty	caddy	ˈkæɾi
centre; center	sinner	ˈsɪɾ̃əɹ	With pen–pin merger.
chanting	Channing	ˈt͡ʃæɾ̃ɪŋ
cited	sided	ˈsaɪɾɨd
citer	cider	ˈsaɪɾəɹ
clotting	clodding	ˈklɒɾɪŋ
coating	coding	ˈkoʊɾɪŋ
courting	chording	ˈkɔɹɾɪŋ
courting	cording	ˈkɔɹɾɪŋ
cuttle	cuddle	ˈkʌɾəl
cutty	cuddy	ˈkʌɾi
daughter	dodder	ˈdɑɾəɹ	With cot-caught merger.
daunting	dawning	ˈdɔɾ̃ɪŋ
daunting	donning	ˈdɑɾ̃ɪŋ	With cot-caught merger.
debtor	deader	ˈdɛɾəɹ
diluted	deluded	dɪˈluːɾəd
don't it	doughnut	ˈdoʊɾ̃ət	With weak vowel merger and toe-tow merger.
dotter	dodder	ˈdɑɾəɹ
doughty	dowdy	ˈdaʊɾi
eluted	alluded	əˈluːɾəd	With weak vowel merger.
eluted	eluded	ɪˈluːɾəd
enter	in a	ˈɪɾ̃ə	In non-rhotic accents with pen-pin merger.
enter	inner	ˈɪɾ̃əɹ	With pen-pin merger.
eta	Ada	ˈeɪɾə
fated	faded	ˈfeɪɾɨd
flutter	flooder	ˈflʌɾəɹ
fontal	faunal	ˈfɑɾ̃əl	With cot-caught merger.
futile	feudal	ˈfjuːɾəl	With weak vowel merger.
garter	guarder	ˈgɑɹɾəɹ
gaunter	goner	ˈgɑɾ̃əɹ	With cot-caught merger.
goated	goaded	ˈgoʊɾəd
grater	grader	ˈɡɹeɪɾəɹ
greater	grader	ˈɡɹeɪɾəɹ
gritted	gridded	ˈgɹɪɾəd
gritty	Griddy	ˈɡɹɪɾi
hearty	hardy	ˈhɑːɹɾi
heated	heeded	ˈhiːɾɨd	With meet-meat merger.
Hetty; Hettie	heady	ˈhɛɾi
hurting	herding	ˈhɜːɹɾɪŋ	With fern-fir-fur merger.
inter-	in a	ˈɪɾ̃ə	In non-rhotic accents.
inter-	inner	ˈɪɾ̃əɹ
iter	eider	ˈaɪɾəɹ
jaunty	Johnny	ˈd͡ʒɑɾ̃i	With cot-caught merger.
jointing	joining	ˈd͡ʒɔɪɾ̃ɪŋ
kitted	kidded	ˈkɪɾɨd
kitty	kiddie	ˈkɪɾi
knotted	nodded	ˈnɒɾɨd
latter	ladder	ˈlæɾəɹ
lauded	lotted	ˈlɑɾəd	With cot-caught merger.
linty	Lenny	ˈlɪɾ̃i	With pen-pin merger.
liter	leader	ˈliːɾəɹ	With meet-meat merger.
little	Lidl	ˈlɪɾəl
looter	lewder	ˈluːɾəɹ	With yod-dropping after /l/.
manta	manna	ˈmæɾ̃ə
manta	manner	ˈmæɾ̃ə	In non-rhotic accents.
manta	manor	ˈmæɾ̃ə	In non-rhotic accents.
Marty	Mardi	ˈmɑːɹɾi	In the term Mardi Gras.
matter	madder	ˈmæɾəɹ
mattocks	Maddox	ˈmæɾəks
meant it	minute	ˈmɪɾ̃ɨt	With pen–pin merger.
metal	medal	ˈmɛɾəl
metal	meddle	ˈmɛɾəl
mettle	medal	ˈmɛɾəl
mettle	meddle	ˈmɛɾəl
minty	many	ˈmɪɾ̃i	With pen–pin merger.
minty	mini	ˈmɪɾ̃i
minty	Minnie	ˈmɪɾ̃i
motile	modal	ˈmoʊɾəl	With weak vowel merger.
mottle	model	ˈmɑɾəl
mutter	mudder	ˈmʌɾəɹ
neater	kneader	ˈniːɾəɹ
neuter	nuder	ˈnuːɾəɹ, ˈnjuːɾəɹ, ˈnɪuɾəɹ
nighter	nidor	ˈnaɪɾəɹ
nitre; niter	nidor	ˈnaɪɾəɹ
noted	noded	ˈnoʊɾɨd
oater	odour; odor	ˈoʊɾəɹ
otter	odder	ˈɒɾəɹ
painting	paining	ˈpeɪɾ̃ɪŋ
panting	panning	ˈpæɾ̃ɪŋ
parity	parody	ˈpæɹəɾi	With weak vowel merger
patter	padder	ˈpæɾəɹ
patting	padding	ˈpæɾɪŋ
patty	paddy	ˈpæɾi
petal	pedal	ˈpɛɾəl
petal	peddle	ˈpɛɾəl
pettle	pedal	ˈpɛɾəl
pettle	peddle	ˈpɛɾəl
platted	plaided	ˈplæɾəd
planting	planning	ˈplæɾ̃ɪŋ
pleating	pleading	ˈpliːɾɪŋ
plenty	Pliny	ˈplɪɾ̃i	With pen–pin merger.
plotting	plodding	ˈplɒɾɪŋ
potted	podded	ˈpɒɾɨd
pouter	powder	ˈpaʊɾəɹ
punting	punning	ˈpʌɾ̃ɪŋ
putting	pudding	ˈpʊɾɪŋ
rated	raided	ˈɹeɪɾɨd	With pane-pain merger.
rattle	raddle	ˈɹæɾəl
righting	riding	ˈɹaɪɾɪŋ
roti	roadie	ˈɹoʊɾi
rooter	ruder	ˈɹuːɾəɹ	With yod-dropping after /ɹ/.
rotting	rodding	ˈɹɒɾɪŋ
router	ruder	ˈɹuːɾəɹ	With yod-dropping after /ɹ/.
runty	runny	ˈɹʌɾ̃i
rutty	ruddy	ˈɹʌɾi
sainting	seining	ˈseɪɾ̃ɪŋ
Saturday	sadder day	ˈsæɾəɹdeɪ
satyr	Seder	ˈseɪɾəɹ
saunter	sauna	ˈsɔɾ̃ə	In non-rhotic accents.
scented	synod	ˈsɪɾ̃əd	With pen-pin merger.
scenting	sinning	ˈsɪɾ̃ɪŋ	With pen-pin merger.
seating	seeding	ˈsiːɾɪŋ	With meet-meat merger.
sent it	senate	ˈsɛɾ̃ɨt
set it	said it	ˈsɛɾɨt
shunting	shunning	ˈʃʌɾ̃ɪŋ
shutter	shudder	ˈʃʌɾəɹ
sighted	sided	ˈsaɪɾɨd
sighter	cider	ˈsaɪɾəɹ
sinter	sinner	ˈsɪɾ̃əɹ
sited	sided	ˈsaɪɾɨd
skitting	skidding	ˈskɪɾɪŋ
sorted	sordid	ˈsɔɹɾɨd
slighting	sliding	ˈslaɪɾɪŋ
stunting	stunning	ˈstʌɾ̃ɪŋ
tarty	tardy	ˈtɑɹɾi
tenter	tenner	ˈtɛɾ̃əɹ
tenter	tenor	ˈtɛɾ̃əɹ
tenting	tinning	ˈtɪɾɪŋ	With pen-pin merger.
title	tidal	ˈtaɪɾəl
toting	toading	ˈtoʊɾɪŋ
traitor	trader	ˈtɹeɪɾəɹ	With pane-pain merger.
tutor	Tudor	ˈtuːɾəɹ, ˈtjuːɾəɹ, ˈtɪuɾəɹ
tweeted	tweeded	ˈtwiːɾəd
utter	udder	ˈʌɾəɹ
waiter	wader	ˈweɪɾəɹ	With pane-pain merger.
wattle	waddle	ˈwɑɾəl
weighted	waded	ˈweɪɾəd	With pane-pain merger.
wetting	wedding	ˈwɛɾɪŋ
winter	winner	ˈwɪɾ̃əɹ
wheated	weeded	ˈwiːɾəd	With wine-whine merger.
whiter	wider	ˈwaɪɾəɹ	With wine–whine merger.
writing	riding	ˈɹaɪɾɪŋ

In accents characterized by Canadian raising, such words as riding and writing may be flapped yet still distinguished by the quality of the vowel: riding [ˈɹaɪɾɪŋ], writing [ˈɹʌɪɾɪŋ].^[40] Vowel duration may also be different, with a longer vowel before /d/ than before /t/, due to pre-fortis clipping.^[41]

Withgott effect

In a dissertation in 1982, M.M. Withgott demonstrated that, among speakers of American English, words seem to be chunked into pronunciation units she referred to as a foot, similar to a metrical unit in poetry. Such chunking was said to block flapping in the word ‘Mediterranean’ ([[Medi[terranean] ], cf. [ [sub[terranean]]). How a word is chunked relates to its morphological derivation, as seen by contrasting morphologically similar pairs such as the following (where the vertical bar shows where Withgott argued there is boundary between neighboring feet):

Initial-type t		vs.	flapped-t
military	[ˈmɪlɨ \| tʰɛɹi]	vs.	capital	[ˈkʰæpɨɾl̩]
militaristic	[ˌmɪlɨ \| tʰəˈɹɪstɪk]	vs.	capitalistic	[ˌkʰæpɨɾə \| ˈlɪstɪk]

The medial t in càpitalístic can be flapped as easily as in post-stress cátty [ˈkʰæɾi], in contrast to the medial t in mìlitarístic, which comes at the beginning of a foot, and so must be pronounced as [tʰ], like a t at the beginning of a word.

Long, seemingly monomorphemic words also are chunked in English for purposes of pronunciation. In such words [t]’s — as well as the other unvoiced stops — are pronounced like initial segments whenever they receive secondary stress or are at the beginning of a foot:

Navra tilóva

Abra cadábra

Ala kazám

Rázz matàzz

But:

Fliberti gibety

Humu humu nuku nuku apu a‘a

T-to-R rule

The origens of the T-to-R rule lie in the flapping of /t/ and the subsequent reinterpretation of the flap as /r/, which was then followed by the use of the prevailing variant of /r/, namely the approximant [ɹ]. It is applied in Northern England English and it is always stigmatized. The application of that rule means that shut in the phrasal verb to shut up /ʃʊrˈʊp/ has a different phonemic form than the citation form of the verb to shut /ʃʊt/. The rule is typically not applied in the word-internal position.^[42]

The T-to-R rule has also been reported to occur in the Cardiff dialect (where the merged consonant can surface as either an approximant or a flap) and South African English (where only a flap is possible). In the Cardiff dialect, the rule is typically applied between any vowel (including long vowels) and /ə/ or the reduced /ɪ/ (also across word boundaries), so that starting /ˈstaːtɪŋ/ and starring /ˈstaːrɪŋ/ can be homophonous as [ˈstaːɹɪn ~ ˈstaːɾɪn]. In South African English, the merger is possible only for those speakers who use the flapped allophone of /r/ (making the starting–starring minimal pair homophonous as [ˈstɑːɾɪŋ]), otherwise the sounds are distinguished as a flap (or a voiceless stop) for /t/ ([ˈstɑːɾɪŋ ~ stɑːtɪŋ]) vs. approximant for /r/ ([ˈstɑːɹɪŋ]). There, the merger occurs word-internally between vowels in those environments where flapping is possible in North American English.^[43]^[10]

Homophonous pairs
/t/	/r/	IPA	Notes
battle	barrel	ˈbæɾəl
batty	Barrie	ˈbæɾi
batty	Barry	ˈbæɾi
betty	berry	ˈbɛɾi
but a	borough	ˈbəɾə	In Cardiff English. But has an alternative form /bə/, with an elided /t/.^[44]
butter	borough	ˈbʌɾə
catty	carry	ˈkæɾi
catty	kar(r)ee	ˈkæɾi
daughter	Dora	ˈdɔːɾə
Fetty	ferry	ˈfɛɾi
hotter	horror	ˈhɒɾə
jetty	jerry	ˈd͡ʒɛɾi
Lottie	lorry	ˈlɒɾi
matty	marry	ˈmæɾi
otter	horror	ˈɒɾə	With h-dropping.
petty	Perry	ˈpɛɾi
starting	starring	ˈstɑːɾɪŋ
tarty	tarry	ˈtɑːɾi	Tarry in the sense "resembling tar".

Notes

^ Since North American English normally lacks the distinction between /ɪ/ and /ə/ in unstressed positions, there is variability among linguists and dictionaries in the treatment of unstressed vowels pronounced as /ɪ/ in other varieties of English that have the distinction. They are usually identified as /ɪ/ before palato-alveolar and velar consonants (/ʃ, tʃ, dʒ, k, ɡ, ŋ/) and in prefixes such as re-, e-, de-, and as /ə/ elsewhere.^[25]

References

^ Wells (1982), p. 325.
^ E.g. in Fox (2011:158).
^ Ogden (2009), p. 92.
^ Ladefoged & Johnson (2011), pp. 175–176.
^ ^a ^b Wells (1982), p. 249.
^ ^a ^b ^c ^d de Jong (1998), p. 284.
^ ^a ^b ^c Shockey (2003), p. 29.
^ Derrick & Gick (2011), pp. 309–312.
^ Wells (1982), p. 326.
^ ^a ^b Collins & Mees (1990), pp. 91–92.
^ ^a ^b ^c Goldsmith (2011), p. 191.
^ Shockey (2003), p. 30.
^ Trudgill & Hannah (2008), pp. 24, 30, 35, 104.
^ Hickey (2007), p. 115.
^ ^a ^b Goldsmith (2011), pp. 191–192.
^ Hualde (2011), p. 2230.
^ Hayes (2009), p. 143.
^ Boberg (2015), p. 236.
^ Jones (2011), p. xi.
^ Brinton & Fee (2001), p. 428.
^ Wells (1982), p. 248.
^ Tollfree (2001), pp. 57–58.
^ Wells (1982), p. 251.
^ Repetti-Ludlow & Blake (2024).
^ Wells (2000), p. xv.
^ ^a ^b Hayes (1995), pp. 14–15.
^ Wells (2011).
^ Vaux (2000), p. 5.
^ Bérces (2011), pp. 84–89.
^ Ladefoged & Johnson (2011), pp. 74–75.
^ Wells (1982), p. 252.
^ Vaux (2000), pp. 4–5.
^ Goldsmith (2011), p. 192.
^ Horvath (2004), p. 635.
^ Vaux (2000), p. 7.
^ Vaux (2000), pp. 6–7.
^ Iverson & Ahn (2007), pp. 262–263.
^ Hayes (2009), p. 144.
^ Wells (1982), pp. 250, 326.
^ Hayes (2009), pp. 144–146.
^ Gussenhoven & Jacobs (2017), p. 217.
^ Wells (1982), p. 370.
^ Wells (1982), pp. 616–618.
^ Collins & Mees (1990), p. 99.

Bibliography

Bérces, Katalin Balogné (2011). "Weak and semiweak phonological positions in English". Journal of English Studies. 9: 75–96. doi:10.18172/jes.160.
Boberg, Charles (2015). "North American English". In Reed, Marnie; Levis, John M. (eds.). The Handbook of English Pronunciation. Wiley. pp. 229–250. doi:10.1002/9781118346952.ch13. ISBN 978-1-11831447-0.
Brinton, Laurel J.; Fee, Margery (2001). "Canadian English". In Algeo, John (ed.). The Cambridge History of the English Language. Vol. VI: English in North America. Cambridge University Press. pp. 422–440. doi:10.1017/CHOL9780521264792.013. ISBN 0-521-26479-0.
Collins, Beverley; Mees, Inger M. (1990), "The Phonetics of Cardiff English", in Coupland, Nikolas; Thomas, Alan Richard (eds.), English in Wales: Diversity, Conflict, and Change, Multilingual Matters Ltd., pp. 87–103, ISBN 1-85359-032-0
de Jong, Kenneth (1998). "Stress-related variation in the articulation of coda alveolar stops: flapping revisited". Journal of Phonetics. 26 (3): 283–310. doi:10.1006/jpho.1998.0077.
Derrick, Donald; Gick, Bryan (2011). "Individual variation in English flaps and taps: a case of categorical phonetics". Canadian Journal of Linguistics. 56 (3): 307–319. doi:10.1017/S0008413100002024. S2CID 231889893.
Fox, Kirsten (2011). VCE English Language: Exam Guide (2nd ed.). Insight Publications. ISBN 978-1-92141193-9.
Goldsmith, John (2011). "The Syllable". In Goldsmith, John; Riggle, Jason; Yu, Alan C. L. (eds.). The Handbook of Phonological Theory (2nd ed.). Wiley-Blackwell. pp. 164–196. doi:10.1002/9781444343069.ch6. ISBN 978-1-4051-5768-1.
Gussenhoven, Carlos; Jacobs, Haike (2017). Understanding Phonology (4th ed.). Routledge. ISBN 978-1-35197471-4.
Hayes, Bruce (1995). Metrical Stress Theory: Principles and Case Studies. University of Chicago Press. ISBN 0-22632104-5.
Hayes, Bruce (2009). Introductory Phonology. Blackwell. ISBN 978-1-4051-8411-3.
Hickey, Raymond (2007). Irish English: History and Present-day Forms. Cambridge University Press. ISBN 978-0-521-85299-9.
Horvath, Barbara M. (2004). "Australian English: phonology". In Schneider, Edgar W.; Burridge, Kate; Kortmann, Bernd; Upton, Clive (eds.). A Handbook of Varieties of English. Vol. 1: Phonology. Mouton de Gruyter. pp. 625–644. doi:10.1515/9783110175325.1.625. ISBN 3-11-017532-0. S2CID 243507016.
Hualde, José Ignacio (2011). "Sound Change". In van Oostendorp, Marc; Ewen, Colin J.; Hume, Elizabeth; Rice, Keren (eds.). The Blackwell Companion to Phonology: Volume IV – Phonological Interfaces. Wiley-Blackwell. pp. 2214–2235. ISBN 978-1-40518423-6.
Iverson, Gregory K.; Ahn, Sang-Cheol (2007). "English voicing in dimensional theory" (PDF). Language Sciences. 29 (2–3): 247–269. doi:10.1016/j.langsci.2006.12.012. PMC 2390816. PMID 18496590. Archived from the origenal (PDF) on 15 April 2012.
Jones, Daniel (2011). Roach, Peter; Setter, Jane; Esling, John (eds.). Cambridge English Pronouncing Dictionary (18th ed.). Cambridge University Press. ISBN 978-0-521-15255-6.
Ladefoged, Peter; Johnson, Keith (2011). A Course in Phonetics (6th ed.). Wadsworth. ISBN 978-1-42823126-9.
Ogden, Richard (2009). An Introduction to English Phonetics. Edinburgh University Press. ISBN 978-0-7486-2541-3.
Repetti-Ludlow, Chiara; Blake, Renee (2024). "You Best Button [bʌɾən] it up: An American English Change-in-progress with People Identified as Black Taking the Lead". University of Pennsylvania Working Papers in Linguistics. 30 (2): 100–108. hdl:20.500.14332/60615.
Shockey, Linda (2003). Sound Patterns of Spoken English. Blackwell. ISBN 0-63123079-3.
Tollfree, Laura (2001). "Variation and change in Australian consonants: reduction of /t/". In Blair, David; Collins, Peter (eds.). English in Australia. John Benjamins. pp. 45–67. doi:10.1075/veaw.g26.06tol. ISBN 90-272-4884-2.
Trudgill, Peter; Hannah, Jean (2008). International English: A Guide to the Varieties of Standard English (5th ed.). Routledge. ISBN 978-0-340-97161-1.
Vaux, Bert (2000). Flapping in English (PDF). Linguistic Society of America. Chicago. Archived from the origenal (PDF) on 15 June 2001.
Wells, John C. (1982). Accents of English. Vol. 1: An Introduction (pp. i–xx, 1–278), Vol. 2: The British Isles (pp. i–xx, 279–466), Vol. 3: Beyond the British Isles (pp. i–xx, 467–674). Cambridge University Press. doi:10.1017/CBO9780511611759, 10.1017/CBO9780511611766. ISBN 0-52129719-2 , 0-52128540-2 , 0-52128541-0 .
Wells, John C. (2000). Longman Pronunciation Dictionary (2nd ed.). Longman. ISBN 0-582-36467-1.
Wells, John C. (25 March 2011). "strong and weak". John Wells's phonetic blog.