Voiced bilabial trill

The voiced bilabial trill is a consonant. It is used in some spoken languages. The letter for this sound in the International Phonetic Alphabet is ⟨⟩. The X-SAMPA symbol for this sound is B\.
In many of the languages that contain the voiced bilabial trill, it only occurs as part of a prenasalised bilabial stop with trilled release, . This developed historically from a prenasalized stop before a relatively high back vowel, such as . In such instances, these sounds are usually still limited to the environment of a following .
Features.
Features of the bilabial trill:
 In most instances, it is only found as the trilled release of a prenasalized stop.