sh (Pinyin) ʂ (IPA)

Voiceless retroflex sibilant
The voiceless retroflex sibilant is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ʂ⟩. Like all the retroflex consonants, the IPA letter is formed by adding a rightward-pointing hook to the bottom of the ess (the letter used for the corresponding alveolar consonant). A distinction can be made between laminal, apical, and sub-apical articulations. Only one language, Toda, appears to have more than one voiceless retroflex sibilant, and it distinguishes subapical palatal from apical postalveolar retroflex sibilants; that is, both the tongue articulation and the place of contact on the roof of the mouth are different.
Some scholars transcribe the laminal variant of this sound as /ʃ/, even though it is not palatalized. In such cases the voiceless palato-alveolar sibilant is transcribed /ʃʲ/.

Features of the voiceless retroflex fricative:

• Its manner of articulation is sibilant fricative, which means it is generally produced by channeling air flow along a groove in the back of the tongue up to the place of articulation, at which point it is focused against the sharp edge of the nearly clenched teeth, causing high-frequency turbulence.
• Its place of articulation is retroflex, which prototypically means it is articulated subapical (with the tip of the tongue curled up), but more generally, it means that it is postalveolar without being palatalized. That is, besides the prototypical sub-apical articulation, the tongue contact can be apical (pointed) or laminal (flat).
• 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.
• 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.
• The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.