Post-alveolar

Postalveolar consonants (sometimes spelled post-alveolar) are consonants articulated with the tongue near or touching the back of the alveolar ridge, farther back in the mouth than the alveolar consonants, which are at the ridge itself but not as far back as the hard palate, the place of articulation for palatal consonants. Examples of postalveolar consonants are the English palato-alveolar consonants [ʃ] [tʃ] [ʒ] [dʒ], as in the words "shill", "'chill", "vision", and "Jill", respectively.

There are a large number of types of postalveolar sounds, especially among the sibilants. The three primary types are palato-alveolar (such as [ʃ ʒ], weakly palatalized), alveolo-palatal (such as [ɕ ʑ], strongly palatalized), and retroflex (such as [ʂ ʐ], unpalatalized). The palato-alveolar and alveolo-palatal subtypes are commonly counted as "palatals" in phonology since they rarely contrast with true palatal consonants.

The sibilant postalveolars (fricatives and affricates) are sometimes called "hush consonants" because they include the sound of English Shhh! (as distinguished from the "hiss consonant" [s], as in Ssss!). For most sounds involving the tongue, the place of articulation can be sufficiently identified just by specifying the point of contact on the upper part of the mouth (for example, velar consonants involve contact on the soft palate and dental consonants involve the teeth), along with any secondary articulation such as palatalization (raising of the tongue body) or labialization (lip rounding). However, among sibilants, and postalveolar sibilants in particular, there are slight differences in the shape of the tongue and the point of contact on the tongue itself, which correspond to large differences in the resulting sound. For example, the alveolar fricative [s] and the three postalveolar fricatives [ɕ ʃ ʂ] differ noticeably both in pitch and sharpness; the order [s ɕ ʃ ʂ] corresponds to progressively lower-pitched and duller (less "hissy" or piercing) sounds. ([s] is the highest-pitched and most piercing, which is the reason that hissing sounds like "Sssst!" or "Psssst!" are typically used to attract someone's attention). As a result, it is necessary to specify many additional subtypes.

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