【ɾ】就是闪音
The terms tap and flap are usually used interchangeably. Peter Ladefoged proposed for a while that it may be useful to distinguish between them; however, his usage has been inconsistent and contradicted itself even between different editions of the same text.[1] The last proposed distinction was that a tap strikes its point of contact directly, as a very brief stop, and 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."[2] This distinction between the alveolar tap and flap can be written in the IPA with tap [ɾ] and flap [ɽ] — the 'retroflex' symbol used for the one that starts with the tongue tip curled back behind the alveolar ridge. This distinction is noticeable in the speech of some American English speakers in distinguishing the words "potty" (tap [ɾ]), and "party" (flap [ɽ]).