Flapping or tapping, also known as alveolar flapping, intervocalic flapping, or t-voicing, is a phonological process found in many dialects of English, especially North American English, Australian English and New Zealand English, by which the consonants /t/ and sometimes also /d/ may be pronounced as a voiced flap in certain positions, particularly between vowels (intervocalic position). In some cases, the effect is perceived by some listeners as the replacement of a /t/ sound with a /d/ sound; for example, the word butter pronounced with flapping may be heard as "budder".[1] In fact, /t/ and sometimes /d/ are pronounced in such positions as an alveolar flap [ɾ], a sound produced by briefly tapping the alveolar ridge with the tongue. Also, in similar positions, the combination /nt/ may be pronounced with a nasalized flap, making winter sound similar or identical to winner.

The flap is also a variant of /r/ in other varieties such as South African English, Scottish English, and older varieties of Received Pronunciation (see Pronunciation of English /r/).[2]


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.[3] Linguists disagree on whether the sound produced in the present process is a flap or a tap, and by extension on whether it is better called flapping or tapping,[4] while flapping has traditionally been more widely used.[5][6]


Flapping 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.[6][7] In Australian, Cockney and Irish English, and to a lesser extent in Received Pronunciation, flapping is present but more occasional and restricted to /t/.[8]

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).[5][9] Across word boundaries, however, it can occur between any two vowels, provided the second vowel begins a word (as in get over [ɡɛɾˈoʊvɚ]).[5][9] This extends to morphological boundaries within compound words (as in whatever [ˌwɑɾˈɛvɚ]).[10] In addition to vowels, segments that may precede the flap include /r/ (as in party)[7][11] and occasionally /l/ (as in faulty).[12][13] Syllabic /l/ may also follow the flap (as in bottle).[14]

Word-medially, 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/),[15] so words like botox, detail and latex are not flapped in spite of the primary stress on the first syllables,[7] while pity, motto and Keating can be.[15] The second syllables in the former set of words can thus be considered as having secondary stress.[5]

Given these intricacies, it is difficult to formulate a phonological rule that accurately predicts flapping.[6] 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.[16]

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]).[17] Others are words such as militaristic which do not get flapped despite capitalistic, for example, being flapped. This may be due to the fact that the deriving word military is not flapped while capital can be, although other theoretical approaches to account for this idiosyncrasy have been proposed.[18][19] In Australian English, numerals thirteen, fourteen and eighteen are often flapped despite the second vowel being stressed.[20][21]

The cluster /nt/ (but not /nd/) in the same environment as flapped /t/ may also be flapped, mostly resulting in a nasal flap [ɾ̃]. Intervocalic /n/ is also often realized as a nasal flap, so words like winter and winner can become homophonous.[22] 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 [ˈwɪɾ̃ɚ] and winner [ˈwɪnɚ].[23] In a limited number of words such as seventy, ninety and carpenter, /nt/ is more frequently pronounced as [nɾ], retaining /n/ and flapping /t/, although it may still become [ɾ̃] in fast speech.[24]


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.[4][25] Some speakers, however, flap only /t/ but not /d/.[26] For speakers with the merger, the following utterances sound the same or almost the same:

Homophonous pairs
/-t-, -nt-/ /-d-, -n-/ IPA Notes
at 'em Adam ˈæɾəm
at 'em add 'em ˈæɾəm
atom Adam ˈæɾəm
atom add 'em ˈæɾəm
banter banner ˈbæɾ̃əɹ
batter badder ˈbæɾəɹ
beating beading ˈbiːɾɪ̈ŋ
betting bedding ˈbɛɾɪ̈ŋ
bitter bidder ˈbɪɾəɹ
boating boding ˈboʊɾɪ̈ŋ, ˈboːɾɪ̈ŋ
butting budding ˈbʌɾɪ̈ŋ
catty caddy ˈkæɾi
center sinner ˈsɪɾ̃əɹ With pen–pin merger.
cited sided ˈsaɪɾɪ̈d
coating coding ˈkoʊɾɪ̈ŋ, ˈkoːɾɪ̈ŋ
cuttle cuddle ˈkʌɾəɫ
cutty cuddy ˈkʌɾi
debtor deader ˈdɛɾəɹ
don't it doughnut ˈdoʊɾ̃ət With weak-vowel merger and toe-tow merger.
futile feudal ˈfjuːɾəɫ, ˈfɪuɾəɫ With weak-vowel merger before /l/.
greater grader ˈɡɹeɪɾəɹ, ˈɡɹeːɾəɹ
hearty hardy ˈhɑɹɾi
heated heeded ˈhiːɾɪ̈d With meet-meat merger.
hurting herding ˈhɜɹɾɪ̈ŋ With fern-fir-fur merger.
inter- inner ˈɪɾ̃əɹ
jointing joining ˈdʒɔɪɾ̃ɪ̈ŋ
kitty kiddie ˈkɪɾi
knotted nodded ˈnɒɾɪ̈d
ladder latter ˈlæɾəɹ
liter leader ˈliːɾəɹ With meet-meat merger.
manta manna ˈmæɾ̃ə
manta manner ˈmæɾ̃ə In non-rhotic accents.
manta manor ˈmæɾ̃ə In non-rhotic accents.
Marty Mardi ˈmɑɹɾi In the term Mardi Gras.
matter madder ˈmæɾəɹ
meant it minute ˈmɪɾ̃ɪ̈t With pen–pin merger.
metal medal ˈmɛɾəɫ
metal meddle ˈmɛɾəɫ
mettle medal ˈmɛɾəɫ
mettle meddle ˈmɛɾəɫ
minty many ˈmɪɾ̃i With pen–pin merger.
minty mini ˈmɪɾ̃i
minty Minnie ˈmɪɾ̃i
neater kneader ˈniːɾəɹ
neuter nuder ˈnuːɾəɹ, ˈnjuːɾəɹ, ˈnɪuɾəɹ
otter odder ˈɒɾəɹ
painting paining ˈpeɪɾ̃ɪ̈ŋ
parity parody ˈpæɹəɾi With weak-vowel merger
patty paddy ˈpæɾi
petal pedal ˈpɛɾəɫ
petal peddle ˈpɛɾəɫ
pettle pedal ˈpɛɾəɫ
pettle peddle ˈpɛɾəɫ
phantom fan 'em ˈfæɾ̃əm
planter planner ˈplæɾ̃əɹ
potted podded ˈpɒɾɪ̈d
rated raided ˈɹeɪɾɪ̈d With pane-pain merger.
rattle raddle ˈɹæɾəɫ
righting riding ˈɹaɪɾɪ̈ŋ
router ruder ˈɹuːɾəɹ With yod-dropping after /ɹ/.
Saturday sadder day ˈsæɾəɹdeɪ
satyr seder ˈseɪɾəɹ
seating seeding ˈsiːɾɪ̈ŋ With meet-meat merger.
sent it senate ˈsɛɾ̃ɪ̈t
set it said it ˈsɛɾɪ̈t
shutter shudder ˈʃʌɾəɹ
sighted sided ˈsaɪɾɪ̈d
sited sided ˈsaɪɾɪ̈d
title tidal ˈtaɪɾəɫ
traitor trader ˈtɹeɪɾəɹ With pane-pain merger.
Tudor tutor ˈtuːɾəɹ, ˈtjuːɾəɹ, ˈtɪuɾəɹ
waiter wader ˈweɪɾəɹ With pane-pain merger.
wetting wedding ˈwɛɾɪ̈ŋ
winter winner ˈwɪɾ̃əɹ
whiter wider ˈwaɪɾəɹ With wine–whine merger.
writing riding ˈɹaɪɾɪ̈ŋ

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].[27] Vowel duration may also be different, with a longer vowel before /d/ than before /t/, due to pre-fortis clipping.[28]

Other languages

A similar process also occurs in other languages, such as the Western Apache language (and other Southern Athabaskan languages). In Western Apache, intervocalic /t/ similarly is realized as [ɾ] in intervocalic position. The process occurs even between words. However, tapping is blocked when /t/ is the initial consonant of a stem so tapping occurs only when /t/ is stem-internal or in a prefix. Unlike English, tapping is not affected by suprasegmentals (stress or tone). Other important examples are Tagalog and some speakers of Finnish, in this case involving /d/ vs. [ɾ].

See also


  1. ^ E.g. in Fox (2011:158).
  2. ^ Ogden (2009), p. 92.
  3. ^ Ladefoged & Johnson (2010), pp. 175–6.
  4. ^ a b Wells (1982), p. 249.
  5. ^ a b c d de Jong (1998), p. 284.
  6. ^ a b c Shockey (2003), p. 29.
  7. ^ a b c Goldsmith (2011), p. 191.
  8. ^ Shockey (2003), p. 30.
  9. ^ a b Goldsmith (2011), pp. 191–2.
  10. ^ Hualde (2011), p. 2230.
  11. ^ Hayes (2009), p. 143.
  12. ^ Boberg (2015), p. 236.
  13. ^ Jones (2011), p. xi.
  14. ^ Wells (1982), p. 248.
  15. ^ a b Hayes (1995), pp. 14–5.
  16. ^ Vaux (2000), pp. 4–5.
  17. ^ Goldsmith (2011), p. 192.
  18. ^ Vaux (2000), p. 5.
  19. ^ Bérces (2011), pp. 84–9.
  20. ^ Horvath (2004), p. 635.
  21. ^ Vaux (2000), p. 7.
  22. ^ Ladefoged & Johnson (2010), pp. 74–5.
  23. ^ Wells (1982), p. 252.
  24. ^ Vaux (2000), pp. 6–7.
  25. ^ Hayes (2009), p. 144.
  26. ^ Wells (1982), p. 250.
  27. ^ Hayes (2009), pp. 144–6.
  28. ^ Gussenhoven & Jacobs (2017), p. 217.


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