A trill is a consonant produced by a repeating vibration (or trilling) of an active articulator, emplying the Bernoulli effect. They are difficult sounds to master and a common target of speech impediments.
A trill may include any amount of contacts; a single-contact trill is similar to a tap, with the exception that taps are usually produced by active movement of articulators.
The IPA recognizes three basic trills:
- Bilabial trill [ʙ] - rareish
- Alveolar trill [r] - a common rhotic sound, sometimes as a realization of a geminate tap
- Uvular trill [ʀ] - common as a rhotic in parts of Europe (eg. French, German, Portuguese). Otherwise mostly found as an allophone of [ʁ].
Other trills are also possible, though not at all places of articulation:
- Labiodental trill, [ʙ̪]: a possible though difficult-to-articulate sound.
- Dental trill, [r̪]: a simple but rarely heard modification of the alveolar trill. UPSID reports a dental trill for e.g. Russian.
- Retroflex trill: Not strictly possible, though Toda appears to feature a phoneme describable as such, basically an alveolar trill with a retroflex flap onset.
- Epiglottal trill: A "purring" sound, associated with strident voice. The symbol [я] is frequently used for this sound.