Flap consonant

In phonetics, a flap or tap is a type of consonantal sound, which is produced with a single contraction of the muscles so that one articulator (such as the tongue) is thrown against another.

The main difference between a flap and a stop is that in a flap there is no buildup of air pressure behind the place of articulation and consequently no release burst. Otherwise a flap is similar to a brief stop.

Flaps also contrast with trills, where the airstream causes the articulator to vibrate. Trills may be realized as a single contact, like a flap, but are variable, whereas a flap is limited to a single contact. When a trill is brief and made with a single contact it is sometimes erroneously described as an (allophonic) flap, but a true flap is an active articulation whereas a trill is a passive articulation. That is, for a tap or flap the tongue makes an active gesture to contact the target place of articulation, whereas with a trill the contact is due to the vibration caused by the airstream rather than any active movement.

Many linguists use the terms tap and flap indiscriminately. Peter Ladefoged proposed for a while that it might be useful to distinguish between them. However, his usage was inconsistent, contradicting itself even between different editions of the same text. One proposed version of the distinction was that a tap strikes its point of contact directly, as a very brief stop, whereas a flap strikes the point of contact tangentially: "Flaps are most typically made by retracting the tongue tip behind the alveolar ridge and moving it forward so that it strikes the ridge in passing." Later, however, he used the term flap in all cases. Subsequent work on the labiodental flap has clarified the issue: flaps involve retraction of the active articulator, and a forward-striking movement. For linguists that do make the distinction, the alveolar tap is transcribed as a fish-hook ar, [ɾ], and while the flap can be transcribed as a small capital dee, [ᴅ], which is not recognized by the IPA. In IPA terms the retroflex flap [ɽ] symbol captures the initial retraction and subsequent forward movement of the tongue tip involved. Otherwise alveolars are typically called taps, and other articulations flaps. No language has been confirmed to contrast a tap and a flap at the same place of articulation. However, such a distinction has been claimed for Norwegian, where the alveolar apical tap /ɾ/ and the post-alveolar/retroflex apical flap /ɽ/ do not differ in place for all speakers.

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