voiced bilabial fricative

A voiced bilabial fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is either a Latin or Greek-style beta, ⟨β⟩.

This letter is also often used to represent a voiced bilabial approximant, though that is more precisely written with a lowering diacritic, that is ⟨β̞⟩. This sound may also be transcribed as an advanced labiodental approximant ⟨ʋ̟⟩, in which case the diacritic is again frequently omitted, since no contrast is likely. It has been proposed that either a turned ⟨β⟩ or reversed ⟨β⟩, among others, be used as a dedicated symbol for the bilabial approximant; however, despite occasional usage, none have gained general acceptance.