Voiceless bilabial approximant

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The voiceless bilabial approximant is a consonant found in the Spanish language. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɸ̞⟩, and the equivalent X-SAMPA symbol is p\_o.

Features of the voiceless bilabial approximant:

• Its manner of articulation is approximant, which means it is produced by narrowing the vocal tract at the place of articulation, but not enough to produce a turbulent airstream.
• Its place of articulation is bilabial, which means it is articulated with both lips.
• Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
• It is an oral consonant, which means that air is exclusively allowed to escape through the mouth.

• It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
• Its airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the intercostal muscles and abdominal muscles, as in most sounds.

• Wetzels, W. Leo; Mascaró, Joan (2001), "The Typology of Voicing and Devoicing" (PDF), Language, 77 (2): 207–244, doi:10.1353/lan.2001.0123, S2CID 28948663