Voiced retroflex trill

A voiced retroflex trill is a contour consonant with the duration of a single segment. Although the tongue starts out in a subapical retroflex position, trilling involves the tip of the tongue and causes it to move forward to the alveolar ridge. Thus, the retroflex trill gives a preceding vowel retroflex coloration, like other retroflex consonants, but the vibration itself is not much different from an alveolar trill. This has been reported in Toda and confirmed with laboratory measurements.

Peter Ladefoged transcribes it with the IPA letter that is defined as a retroflex flap, ⟨ɽ⟩, in broad transcription. In narrower transcription ⟨ɽ͡r⟩ is appropriate.

Other languages reported to have an (apico-)retroflex trill are Wintu and Lardil. In these languages the tip of the tongue approaches the hard palate, but the articulation is not subapical as it is in Toda. The trill has a retroflex flap allophone that occurs between vowels.

Several languages have been reported to have trilled retroflex affricates, such as [ɳɖ͡ɽ̝] and [ʈ͡ɽ̝̊], including Mapudungun, Malagasy, Fijian, and Baima. However, the exact articulation is rarely clear from descriptions. In Fijian, for example, subsequent investigation revealed that the sound (orthographic dr) is rarely trilled, but is usually realized as a postalveolar stop [n̠d̠] instead. In Mapudungun, the sound (orthographic tr) is strongly retroflex, causing /l/ and /r/ following the subsequent vowel to become retroflex as well. The southern dialect varies between /ʈɽ/ and /ʈʂ/, but it is not clear whether the letter ⟨ɽ⟩ is intended to represent a flap, a trill, or a non-sibilant fricative.