Voiceless linguolabial fricative

The voiceless linguolabial fricative is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents it is ⟨θ̼⟩ or ⟨ɸ̺⟩.

Features

Features:

• Its manner of articulation is fricative, which means it is produced by constricting air flow through a narrow channel at the place of articulation, causing turbulence.
• Its place of articulation is linguolabial, which means it is articulated with the tongue against the upper lip.
• 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 air is allowed to escape through the mouth only.
• The
  intercostal muscles and abdominal muscles
  , as in most sounds.