Voiceless postalveolar fricative - Definition and Overview

The voiceless postalveolar fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ʃ, and the equivalent X-SAMPA symbol is S. The voiceless postalveolar fricative occurs in English, and it is the sound denoted by the letters "sh" in shoe, the letters "ss" in passion, or the letters "ti" in donation.

IPA - Unicode	ʃ
IPA - image
X-SAMPA	S
Kirshenbaum	S
Sound sample

Features of this consonant:

• 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 postalveolar which means it is articulated with the tip of the tongue between the alveolar ridge and the palate, but closer to the alveolar ridge than for alveolo-palatal consonants.
• Its phonation type is voiceless, which means it is produced without vibrations of the vocal cords.
• It is an oral consonant, which means air is allowed to escape through the mouth.
• It is a central consonant, which means it is produced by allowing the airstream to flow over the middle of the tongue, rather than the sides.
• The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.