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.
| IPA | Description | Example | |||
|---|---|---|---|---|---|
| Language | Orthography | IPA | Meaning | ||
| ɾ | alveolar tap | North American English | latter | /læɾɚ/ | "latter" |
| ɺ | alveolar lateral flap | Japanese | ラーメン | /ɺaːmeɴ/ | "ramen" |
| ɽ | retroflex flap | Warlpiri | dupa (?) | /ɽupa/ | "windbreak" |
| labiodental flap | Karang | "animal" | |||
Spanish features a good illustration of an alveolar flap, contrasting it with a trill: pero /peɾo/ "but" vs. perro /pero/ "dog". Among the Germanic languages, this allophone occurs in American English and in Northern Low Saxon (“Low German”). In American English it tends to be an allophone of intervocalic /t/ (as in "butter," "later," "fattest" and "total"). In a number of Low Saxon dialects it occurs as an allophone of intervocalic /d/ or /t/; e.g. bäden /beeden/ → ['beːɾn] ‘to pray’, ‘to request’, gah to Bedde! /gaa tou bede/ → [ˌgɑːtoʊ'beɾe] ‘go to bed!’, Water /vaater/ → ['vɑːɾɜ] ‘water’, Vadder /fater/ → ['faɾɜ] ‘father’. (In some dialects this has resulted in reanalysis and a shift to /r/; thus bären ['beːrn], to Berre [toʊ'bere], Warer ['vɑːrɜ], Varrer ['farɜ].) Occurrence varies; in some Low Saxon dialects it affects both /t/ and /d/, while in others it affects only /d/.
A retroflex flap is also common in Norwegian dialects and some Swedish dialects.
However, it is also possible that many of these languages do not have a lateral-central contrast at all, so that even a consistently neutral articulation may be perceived as sometimes lateral [ɺ] or [l], sometimes central [ɾ]. This has been suggested to be the case for Japanese, for example.
The Iwaidja language of Australia has both alveolar and retroflex lateral flaps, and perhaps a palatal lateral flap as well. (However, the latter is rare and may be a palatalized alveolar lateral flap rather than a separate phoneme.) These contrast with lateral approximants at the same positions, as well as a central retroflex flap [ɽ], alveolar trill [r], and retroflex approximant [ɻ].
A velar lateral flap may exist as an allophone in a few languages of New Guinea.
The symbol for the alveolar lateral flap is the basis for the expected (though not officially recognized) symbol for the retroflex lateral flap,
Symbols such as these are uncommon, but are becoming more frequent now that font-editing software has become accessible. Note however that besides not being sanctioned by the IPA, there are no Unicode values for them. However, the retroflex lateral flap may be written as a digraph with the right-tail diacritic, [ɺ̡].
The palatal and velar lateral flaps may be represented with a short diacritic over the letter for the homorganic approximant, although the diacritic would need to appear under the palatal due to its ascender: .
The only common non-rhotic flap is the labiodental flap, found throughout central Africa in languages such as Margi. In 2005, the IPA adopted a right-hook vee,
for this sound. Previously, it had been transcribed with the use of the breve diacritic, [v̆], or other ad hoc symbols.
Other flaps are much less common. They include a bilabial flap in Banda, which may be an allophone of the labiodental flap, and a velar lateral flap as an allophone in Kanite and Melpa. These are often transcribed with the breve diacritic, as . Note here that, like a velar trill, a central velar flap or tap is not possible because the tongue and soft palate cannot move together easily enough to produce a sound.
If other flaps are found, the breve diacritic could be used to represent them, but would more properly be combined with the symbol for the corresponding voiced plosive. A palatal or uvular flap, which unlike a velar flap is believed to be articulatorily possible, could be represented this way (by ).