Labial consonants are speech sounds produced primarily with the lips. As a basic class of places of articulation, labials are defined by lip involvement and include several manners of articulation such as stops, nasals, fricatives and approximants. For a general account of how sounds are shaped in the mouth see articulation.

Characteristics

Labial sounds share the common property that closure, constriction, or approximation occurs at or near the lips. They are distinguished from other places of articulation (like dental, alveolar or velar) by the participation of one or both lips. Labial gestures may occur alone or together with secondary gestures such as rounding; they can be voiced or voiceless and may be oral or nasal.

Major types and examples

  • Bilabial — both lips meet. Typical examples: /p/, /b/ (stops), /m/ (nasal). See further notes on bilabial consonants.
  • Labiodental — lower lip against upper teeth. Typical examples: /f/, /v/ (fricatives); some languages also have labiodental nasals or approximants. See labiodental consonants.
  • Labio-velar and rounded labials — combined gestures such as /w/ (a labiovelar approximant) involve the lips plus another place like the velum.

These categories cover most common labial sounds, but other rare types exist (for example, linguolabials where the tongue contacts the upper lip).

History, distribution and significance

Labials are among the most widespread consonants cross-linguistically: simple bilabials like /p, b, m/ appear in most of the world's languages and are often early-acquired by children. Historical sound changes can create or remove labial contrasts (for instance, through labialization of velars or the loss of labiodentals), and labials play an important role in phonological patterns and orthographies.

In applied settings—language teaching, phonetics, and speech therapy—labials are studied for their distinct visible articulation and susceptibility to substitution errors. Notable distinctions to remember include the difference between bilabial and labiodental contact, the presence of secondary labialization, and rare labial types found in a few languages.