Flapping

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 "posh" affricate [tsʰ] and the "rough" glottal stop [ʔ].^[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]