bilabiale

Bilabiale, in phonetics often rendered as bilabial in English, refers to a class of consonants articulated with both lips. The core bilabial sounds are the stops p (voiceless) and b (voiced), and the nasal m. These are produced by bringing the upper and lower lips together and briefly stopping or constricting the airflow before release or resonance.

Beyond the basic stops and nasal, some languages feature bilabial fricatives and related sounds. The voiceless bilabial fricative is commonly written as [ɸ], while the voiced bilabial fricative is [β]. Depending on the language, these can be phonemic or occur as allophonic realizations of other bilabial phonemes. An additional bilabial-type sound is the approximant [β̞] or, in many descriptions, the labio-velar approximant [w], which involves both lips plus a velar place of articulation and is sometimes discussed in relation to bilabials.

In linguistic typology, bilabial consonants are among the most widespread across the world’s languages. They typically contrast with consonants produced at other places of articulation, such as labiodental, dental, alveolar, and velar groups. The distribution of bilabials varies by language, including which manners of articulation are present (stops, nasals, fricatives, approximants) and how they interact with phonological processes like assimilation and voicing. Etymologically, the term derives from Latin roots meaning “two lips.”

See also: labial consonants, place of articulation, voicing, stop, nasal, fricative, approximant.