Postalveolar consonants

Postalveolar consonants (sometimes spelled post-alveolar) are consonants articulated with the tongue near or touching the back of the alveolar ridge, further 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 "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 (e.g., weakly palatalized); alveolo-palatal (e.g. , strongly palatalized); and retroflex (e.g. , unpalatalized). The palato-alveolar and alveolo-palatal subtypes are commonly counted as "palatals" in phonology, since they rarely contrast with true palatal consonants.

Sibilant postalveolars
The sibilant postalveolars (i.e. fricatives and affricates) are sometimes called "hush consonants" because they include the sound of English Shhh!. 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 (e.g. the soft palate velar consonants or between the teeth for interdental consonants), 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, slight differences in the shape of the tongue and the point of contact on the tongue correspond to large differences in the resulting sound. 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 front of the tongue). From least to most palatalized, these are retroflex (e.g., unpalatalized); palato-alveolar (e.g. , weakly palatalized); and alveolo-palatal (e.g. , strongly palatalized). The increasing palatalization corresponds to progressively higher-pitched and sharper-sounding consonants. Speaking non-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 pronounced forcefully and with a strong American "r"; while 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 (bunched-up or domed) tongue, i.e. the front, central part of the tongue is somewhat raised compared to the tip, back and sides, which gives it weak palatalization. For retroflex sounds, the tongue shape is either concave (usually when apical or subapical, i.e. when made with the tip of the tongue), or flat (usually when laminal, i.e. 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, called 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, while 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 (e.g. alveolo-palatal) sounds occur only with laminal articulation. Furthermore, 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); such sounds occur particularly in the Dravidian languages. Alveolar retroflex sounds tend to be apical (so-called "apico-alveolar sibilants"), which are well-known from their occurrence in northern Iberia, like in Astur-Leonese, Basque, Castilian Spanish, Catalan, Galician and Northern Portuguese. As a result of the large number of retroflex varieties, differing IPA symbols are sometimes used; for example, more forward articulations are often denoted (with a retracted diacritic attached to alveolar ) rather than. For more information on these differing varieties, see the article on retroflex consonants.

Position of tongue tip (laminal "closed")
There is an additional distinction that can be made among tongue-down laminal sounds, depending on where exactly behind the lower teeth the tongue tip is placed. A little ways back from the lower teeth is a hollowed area (or pit) in the lower surface of the mouth. When the tongue tip rests in this 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), while for the tongue-down alveolar consonants, the tongue tip rests against the teeth (no sublingual cavity); this accentuates the hissing vs. hushing distinction of these sounds.

However, the palato-alveolar sibilants in the Northwest Caucasian languages such as Ubykh have the tongue tip resting directly against the lower teeth rather than in the hollowed area. Ladefoged and Maddieson term this a "closed laminal postalveolar" articulation, which gives the sounds a quality that Catford describes as "hissing-hushing" sounds. Catford transcribes them as (note: this is not IPA notation). A laminal "closed" articulation could also be made with alveolo-palatal sibilants and a laminal "non-closed" articulation with alveolar sibilants, but no language appears to do so. In addition, no language seems to have a minimal contrast between two sounds based only on the "closed"/"non-closed" variation, with no concomitant articulatory distinctions (i.e. for all languages, including the Northwest Caucasian languages, if the language has two laminal sibilants, one of which is "closed" while the other is "non-closed", they will also differ in some other ways).

Examples
A few languages distinguish three different postalveolar sibilant tongue shapes. Examples are the Tibeto-Burman languages Northern Qiang and Southern Qiang, which make such a distinction among affricates (but only a two-way distinction among fricatives) and the Northwest Caucasian language Ubkyh (whose palato-alveolar is of the laminal "closed" type, sometimes indicated phonetically as ). More common are languages such as Mandarin Chinese and Polish that distinguish two postalveolar sibilants, typically because they are maximally distinct. For more information on possible distinctions, see the article on sibilants.

The attested possibilities, with exemplar languages, are as follows. Note that the IPA diacritics are simplified; some articulations would require two diacritics to be fully specified, but only one is used in order to keep the results legible without the need for OpenType IPA fonts. Also, Ladefoged has resurrected an obsolete IPA symbol, the under dot, to indicate apical postalveolar (normally included in the category of retroflex consonants), and that notation is used here. (Note that the notation is sometimes reversed; either may also be called 'retroflex' and written .)

Postalveolar non-sibilants
Non-sibilant sounds can also be made in the postalveolar region. For these sounds, however, the number of acoustically distinct variations is significantly reduced. The primary distinction for such sounds is between laminal palatalized and apical retroflex non-palatalized. (Subapical retroflex non-sibilants also occur but tend to be palatal, as for sibilants.)

Non-palatalized (retroflex)
Retroflex stops, nasals and laterals (e.g. ) occur in a number of languages across the world. Examples are the South Asian languages (e.g. Hindi) and various East Asian languages such as Vietnamese. The sounds are fairly rare in European languages but do occur, for example, in Swedish, where they are often considered to be allophones of sequences such as or. Also, for some languages that distinguish "dental" vs. "alveolar" stops and nasals, these are actually articulated closer to prealveolar and postalveolar, respectively.

The normal rhotic consonant (r-sound) in American English is a retroflex approximant  (the equivalent in British English is an alveolar approximant ). Retroflex rhotics of various sorts, especially approximants and flaps occur commonly in the world's languages. Some languages also have retroflex trills. Malayalam in fact has two trills, at least for many speakers &mdash; vs. &mdash; the latter of which is retroflex. Toda is particularly unusual is having six trills, including a palatalized/non-palatalized distinction and a three-way place distinction among dental, alveolar and retroflex trills.

Palatalized
Palatalized postalveolar non-sibilants are usually considered to be alveolo-palatal. Some non-sibilant sounds in some languages are said to be palato-alveolar rather than alveolo-palatal, but in practice it is unclear if there is any consistent acoustic distinction between the two types of sounds.

In phonological descriptions, alveolo-palatal postalveolar non-sibilants are usually not distinguished as such. Instead, they are considered to be variants of either palatal non-sibilants (e.g., or of palatalized alveolar non-sibilants (e.g. ). Even these two types are often not distinguished among nasals and laterals, as the vast majority of languages have only one palatalized nasal or lateral in the   For example, the sound described as a "palatal lateral" in various Romance languages and often indicated as  varies from an actual palatal sound  in Italian to an alveolo-palatal  in Catalan to a palatalized alveolar  in Brazilian Portuguese.

The IPA does not have specific symbols for alveolo-palatal non-sibilants, but they can be denoted using a combination of the palatalized and retracted diacritics, e.g. . Sinologists often use special symbols for alveolo-palatal non-sibilants, e.g., created by analogy with the curls used to mark alveolo-palatal sibilants. However, the actual sounds indicated using these symbols are often palatal or palatalized alveolar rather than alveolo-palatal, just like the variation for symbols like. (The decision to use the special alveolo-palatal symbols in Sinological circles is largely based on distributional similarities between the sounds in question and the alveolo-palatal sibilants, which are prominent in many East Asian languages.)

However, a few languages do distinguish alveolo-palatal sounds from other palatalized non-sibilants in the dental-to-palatal region. Many dialects of Irish in fact have a three-way distinction among palatalized nasals between dorsal palatal, laminal alveolo-palatal , and apical palatalized alveolar. (Note that, as is typical with oppositions among similar sounds in a single language, the sounds are maximally different in that each one differs both in the point of contact on the tongue &mdash; dorsal vs. laminal vs. apical &mdash; and the roof of the mouth &mdash; palatal vs. postalveolar vs. alveolar &mdash; from all others.) The other dialects have lost one of the two palatalized coronals, but still have a two-way distinction. A similar distinction between palatal  and alveolo-palatal  exists in some non-standard forms of Malayalam.

Examples
Some languages distinguish palatalized (alveolo-palatal) and non-palatalized (retroflex) postalveolar nasals and/or laterals. Some of the most notable distinctions among acute (dental-to-palatal) non-sibilants are as follows.

Some Australian languages distinguish four coronal nasals and laterals: laminal dental, apical alveolar , laminal postalveolar (palatalized) , and apical postalveolar (retroflex).

The non-standard Malayalam dialects mentioned above have five acute (including four coronal) nasals: laminal dental, apical alveolar , laminal postalveolar (palatalized) , subapical palatal (retroflex) , and dorsal palatal (palatalized) (in addition to labial  and velar ). Standard Malayalam is missing the laminal palatalized postalveolar.

The conservative Irish dialects mentioned above likewise have five acute nasals, again including four coronal; however, only four different primary articulations are involved, as a secondary velarized/palatalized distinction is at play. The sounds in question are: laminal dental velarized, apical alveolar velarized , apical alveolar palatalized , laminal postalveolar (palatalized) , and dorsal palatal (in addition to labial velarized , labial palatalized  and velar ). These eight sounds participate in four velarized/palatalized pairs: ; ; ;. Other dialects have variously reduced the four coronal nasals to three or two.

Postalveolar clicks
There are two postalveolar click consonant releases that can occur, commonly described as "postalveolar" and "palatal" but perhaps more accurately described as apical and laminal postalveolar, respectively: