Epiglottal consonants are often allophonically trilled, and in some languages the trill is the primary realization of the consonant. There is no official symbol for this in the IPA, but occasionally a small capital [Я] will be used. An epiglottal consonant is a consonant that is articulated with the epiglottis against the back of the pharynx. ...
In addition, strident vowels are defined by an accompanying epiglottal trill.
In phonetics, a trill is a consonantal sound produced by vibrations between the articulator and the place of articulation.
Whereas with a flap (or tap), a specific gesture is used to strike the active articulator against the passive one, in the case of a trill the articulator is held in place, where the airstream causes it to vibrate.
Epiglottal consonants are often allophonically trilled, and in some languages the trill is the primary realization of the consonant.