intervocalic alveolar flapping

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  and 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 ) – 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.