Intervocalic alveolar flapping

:"Flapping" redirects here. For other uses of the term, see Flap."

Intervocalic alveolar flapping (more accurately 'tapping', see below) is a phonological process found in many dialects of English, especially North American English, by which prevocalic (preceding a vowel) IPA|/t/ and IPA|/d/ surface as the alveolar tap IPA| [ɾ] after sonorants other than IPA|/ŋ/, /m/, and (in some environments) /l/.
*after vowel: butter
*after r: barter
*after l: faculty (but not immediately post-tonic: alter → IPA|al [tʰ] er, not IPA|*al [ɾ] er)

The term "flap" is often used as a synonym for the term "tap", but the two can be distinguished phonetically. 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. A tap involves a rapid backwards and forwards movement of the tongue tip. The sound referred to here is the alveolar tap IPA| [ɾ] , not the flap IPA| [ɽ] , and hence "tapping" is the correct term from a phonetic point of view (see also Flap consonant). The term "flapping" is, however, ingrained in much of the phonological literature, so it is retained here. [Giegerich, Heinz J. (1992). "English Phonology", pp. 225, 241. Cambridge University Press.] However, no languages are known to contrast taps and flaps in the first place.

Flapping/tapping is a specific type of lenition, specifically intervocalic weakening. For people with the merger these following words sound the same or almost the same:

* betting/bedding
* boating/boding
* coating/coding
* grater/grader
* hearty/hardy
* kitty/kiddie
* liter/leader
* latter/ladder
* matter/madder
* metal/medal
* Patty/Paddy
* rater/raider
* shutter/shudder
* waiter/wader

For most (but not all) speakers the merger does not occur when an intervocalic IPA|/t/ or IPA|/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 IPA|/t/ and IPA|/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.

Flapping/tapping does not occur in most dialects when the IPA|/t/ or IPA|/d/ immediately precedes a stressed vowel, as in "retail", but can flap/tap in this environment when it spans a word boundary, as in "got it" → IPA| [gɑɾɪt] , and when a word boundary is embedded within a word, as in "buttinsky". Australian English also flaps/taps word-internally before a stressed vowel in words like "fourteen".

In many accents, such words as "riding" and "writing" 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 IPA|/aɪ/ phoneme preceding it. Thus for many North Americans, "riding" is IPA| [ɹɑɪɾɪŋ] while "writing" is IPA| [ɹɐɪɾɪŋ] . Vowel duration may also be different, with a longer vowel before tap realisations of /d/ than before tap realisations 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.

The cluster IPA| [nt] can also be flapped/tapped; the IPA symbol for a nasal tap is IPA| [ɾ̃] . As a result, in quick speech, words like "winner" and "winter" can become homophonous. Flapping/tapping does not occur for most speakers in words like 'carpenter' and 'ninety', which instead surface with IPA| [d] . [ [http://alt-usage-english.org/center_for_dentists.wav "a sentence about a center for dentists, at the frontal edge of the continent, by the Atlantic ocean"] .]

A similar process also occurs in other languages, such as Western Apache (and other Southern Athabaskan languages). In Western Apache, intervocalic IPA|/t/ similarly is realized as IPA| [ɾ] in intervocalic position. This process occurs even over word boundaries. However, tapping is blocked when IPA|/t/ is the initial consonant of a stem (in other words tapping occurs only when IPA|/t/ is stem-internal or in a prefix). Unlike English, tapping is not affected by suprasegmentals (in other words stress or tone).

References

ee also

* Regional accents of English speakers