Flapping or tapping, also known as alveolar flapping or intervocalic flapping, 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 /d/ may be pronounced as a flap (tap) 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". In fact, both /t/ and /d/ are replaced in such positions by an alveolar flap (or tap; IPA symbol [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, or just with an [n] sound, so that winter may sound similar or identical to winner.
The terms flap and tap are often used synonymously, although some authors make a distinction between them. According to Heinz Giegerich, a flap involves a rapid movement of the tongue tip from a retracted vertical position to a (more or less) horizontal position, during which the tongue tip brushes the alveolar ridge, while a tap involves a rapid upward and downward movement of the tongue tip, the upward movement being voluntary and the lowering involuntary. On this view, the sound referred to here is the alveolar tap, rather than the flap, even though the term "flapping" is ingrained in much of the phonological literature.
Even though taps and flaps are sometimes distinguished phonetically, no languages are known to contrast them, and they are assigned only one set of symbols in the International Phonetic Alphabet (IPA). The symbol for the alveolar tap (flap) discussed here is ɾ.
Flapping/tapping may occur when /t/ or /d/ occurs between two vowels, as in butter, writing, wedding, loader. However it does not occur in most dialects when the /t/ or /d/ immediately precedes a stressed vowel, as in attack [əˈtʰæk], but they can tap in this environment when it spans a word boundary, as in got over [ɡɑɾˈoʊvɚ], and when a word boundary is embedded within a word, as in buttinsky [bʌɾˈɪnski]. Australian English also taps word-internally before a stressed vowel in words like fourteen.
The cluster /nt/ can also be tapped, being pronounced with a nasalized tap (IPA symbol ɾ̃). In quick speech this may become simply [n], so that words like winner and winter can become homophonous. Tapping does not occur for most speakers in words like carpenter and ninety, which instead surface with [d].
It is also reported that tapping may occur after r, as in barter, and sometimes after l, as in faculty (but not immediately after the stress: alter → [ɔːɫtəɹ], not [*ɔːɫɾəɹ]).
Flapping/tapping 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. For speakers with the merger these following utterances sound the same or almost the same (click "show" to display the table):
For most (but not all) speakers the merger does not occur when an intervocalic /t/ or /d/ is followed by a syllabic n, so written and ridden remain distinct. A non-negligible number of speakers (including pockets in the Boston area) lack the rule that glottalizes t and d before syllabic n, and therefore flap/tap /t/ and /d/ in this environment. Pairs like potent : impotent, with the former having a preglottalized unreleased t or a glottal stop (but not a flap/tap) and the latter having either an aspirated t or a flap/tap, suggest that the level of stress on the preceding vowel may play a role in the applicability of glottalization and flapping/tapping before syllabic n. Some speakers in the Pacific Northwest turn /t/ into a flap but not /d/, so writer and rider remain distinct even though the long i is pronounced the same in both words.
In accents characterized by Canadian raising, such words as riding and writing, both of which have an alveolar flap, continue to be distinguished by the preceding vowel: though the consonant distinction is neutralized, the underlying voice distinction continues to select the allophone of the /aɪ/ phoneme preceding it. Thus for many North Americans, riding is [ɹaɪɾɪŋ] while writing is [ɹɐɪɾɪŋ]. Vowel duration may also be different, with a longer vowel before tap realizations of /d/ than before tap realizations of /t/. At the phonetic level, the contrast between /t/ and /d/ may be maintained by these non-local cues, though as the cues are quite subtle, they may not be acquired/perceived by others. A merger of /t, d/ can then be said to have occurred in this context.
A similar process also occurs in other languages, such as Western Apache (and other Southern Athabaskan languages). In Western Apache, intervocalic /t/ similarly is realized as [ɾ] in intervocalic position. This process occurs even over word boundaries. However, tapping is blocked when /t/ is the initial consonant of a stem (in other words tapping occurs only when /t/ is stem-internal or in a prefix). Unlike English, tapping is not affected by suprasegmentals (in other words stress or tone).
- See for example: Kirsten Fox, English Language Exam Guide, Insight Publications, 2011, p. 158.
- Giegerich, Heinz J. (1992). English Phonology, pp. 225, 241. Cambridge University Press.
- Recording of "a sentence about a center for dentists, at the frontal edge of the continent, by the Atlantic ocean", demonstrating flapping of /nt/