Definition:
A flap (also called a tap) is a consonant sound produced by a single, rapid strike of the tongue tip against the alveolar ridge (the ridge just behind the upper front teeth), too brief to produce complete closure. The International Phonetic Alphabet symbol is [ɾ].
Flap in American English
In most varieties of American and Canadian English, the phonemes /t/ and /d/ are both realised as the flap [ɾ] when they occur between vowels and the preceding vowel is stressed:
| Word | Phonemic | Phonetic |
|---|---|---|
| butter | /ˈbʌtər/ | [ˈbʌɾər] |
| ladder | /ˈlædər/ | [ˈlæɾər] |
| water | /ˈwɔːtər/ | [ˈwɔːɾər] |
| matter | /ˈmætər/ | [ˈmæɾər] |
| body | /ˈbɒdi/ | [ˈbɒɾi] |
This process — called flapping or tapping — is why butter and budder, or metal and medal, sound identical to many American English listeners.
Flap in Japanese
The Japanese phoneme typically romanised as r (ら row: ら り る れ ろ) is a dental/alveolar flap [ɾ], distinct from both the English /l/ and the English /r/ (a retroflex approximant). This is why:
- Japanese learners often struggle to distinguish and produce English /l/ vs /r/
- English learners often mispronounce Japanese ら as English /l/ or /r/ rather than [ɾ]
Flap vs. Trill
A trill (like the Spanish rolled /r/ or rrr) involves multiple rapid contacts; a flap involves only a single contact. They are distinct consonant types, though both use the IPA base symbol /r/ in various orthographies.
Relevance for L2 Learners
- Japanese learners of English: The Japanese /ɾ/ is acoustically between English /l/ and /r/ — neither a lateral nor a retroflex. Training ear to perceive [ɾ] ≠ /l/ ≠ /r/ is often the key intervention.
- English learners of Japanese: American English speakers may be able to leverage their native flapping rule as a starting point for the Japanese /r/.