Postalveolar consonants

Postalveolar or post-alveolar consonants are consonants articulated with the tongue near or touching the ''back'' of the alveolar ridge. Articulation is 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 , as in the words "ship", "'chill", "vision", and "jump", respectively.

There are many types of postalveolar sounds—especially among the sibilants. The three primary types are '' palato-alveolar'' (such as , weakly palatalized), ''alveolo-palatal'' (such as , strongly palatalized), and ''retroflex'' (such as , unpalatalized). The palato-alveolar and alveolo-palatal subtypes are commonly counted as "palatals" in phonology since they rarely contrast with true palatal consonants.

Postalveolar sibilants

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, particularly postalveolar sibilants, 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 and the three postalveolar fricatives differ noticeably both in pitch and sharpness; the order corresponds to progressively lower-pitched and duller (less "hissy" or piercing) sounds. ( 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.

Tongue shape

The main distinction is the shape of the tongue, which corresponds to differing degrees of palatalization (raising of the body of the tongue). From least to most palatalized, they are ''retroflex'' (such as , unpalatalized); '' palato-alveolar'' (such as , weakly palatalized); and ''alveolo-palatal'' (such as , strongly palatalized). The increasing palatalization corresponds to progressively higher-pitched and sharper-sounding consonants.

Less technically, the retroflex consonant sounds somewhat like a mixture between the regular English of "ship" and the "h" at the beginning of "heard", especially when it is pronounced forcefully and with a strong American "r". The alveolo-palatal consonant sounds like a strongly palatalized version of , somewhat like "nourish you".

Palato-alveolar sounds are normally described as having a convex (a bunched-up or ''domed'') tongue. The front, central part of the tongue is somewhat raised compared to the tip, back and sides, which gives it a weak palatalization. For retroflex sounds, the tongue shape is either concave (usually when apical or subapical, made with the tip of the tongue) or flat (usually when laminal, made with the area behind the tongue tip). For alveolo-palatal sounds, the front half of the tongue is flat and raised so that it closely parallels the upper surface of the mouth, from the teeth to the hard palate. Behind that is a sudden convex bend.

The following table shows the three types of postalveolar sibilant fricatives defined in the IPA:

Point of tongue contact (laminal, apical, subapical)

A second variable is whether the contact occurs with the very tip of the tongue (an ''apical'' articulation ), with the surface just above the tip, the ''blade'' of the tongue (a ''laminal'' articulation ), or with the underside of the tip (a ''subapical'' articulation). Apical and subapical articulations are always "tongue-up", with the tip of the tongue above the teeth, and laminal articulations are often "tongue-down", with the tip of the tongue behind the lower teeth.

The upward curvature of the tongue tip to make apical or subapical contact renders palatalization more difficult so domed (palato-alveolar) consonants are not attested with subapical articulation and fully palatalized (such as alveolo-palatal) sounds occur only with laminal articulation. Also, the apical-laminal distinction among palato-alveolar sounds makes little (although presumably non-zero) perceptible difference; both articulations, in fact, occur among English-speakers.

As a result, the differing points of tongue contact (laminal, apical and subapical) are significant largely for retroflex sounds. Retroflex sounds can also occur outside of the postalveolar region, ranging from as far back as the hard palate to as far forward as the alveolar region behind the teeth. Subapical retroflex sounds are often palatal (and vice versa), which occur particularly in the Dravidian languages.

Position of tongue tip (laminal "closed")

There is an additional distinction that can be made among tongue-down laminal sounds, depending on exactly where behind the lower teeth the tongue tip is placed. A bit behind the lower teeth is a hollow area (or pit) in the lower surface of the mouth. When the tongue tip rests in the hollowed area, there is an empty space below the tongue (a ''sublingual cavity''), which results in a relatively more "hushing" sound. When the tip of the tongue rests against the lower teeth, there is no sublingual cavity, resulting in a more "hissing" sound. Generally, the tongue-down postalveolar consonants have the tongue tip on the hollowed area (with a sublingual cavity), whereas for the tongue-down alveolar consonants, the tongue tip rests against the teeth (no sublingual cavity), which accentuates the hissing vs. hushing distinction of these sounds.

However, the palato-alveolar sibilants in Northwest Caucasian languages such as the extinct Ubykh have the tongue tip resting directly against the lower teeth rather than in the hollowed area. Ladefoged and Maddieson term it a "''closed'' laminal postalveolar" articulation, which gives the sounds a quality that Catford describes as "hissing-hushing" sounds. Catford transcribes them as (that is not IPA notation; the obsolete IPA {{R from other capitalisation ...