Voiceless alveolar sibilant
The voiceless alveolar sibilant is a common consonant sound in vocal languages. It is the sound in English words such as sea and pass, and is represented in the International Phonetic Alphabet with ⟨s⟩. It has a characteristic high-pitched, highly perceptible hissing sound. For this reason, it is often used to get someone's attention, using a call often written as sssst! or psssst!.
The voiceless alveolar sibilant [s] is one of the most common sounds cross-linguistically. If a language has fricatives, it will most likely have [s]. However, some languages have a related sibilant sound, such as [ʃ], but no [s]. In addition, sibilants are absent from Australian Aboriginal languages, where fricatives are rare; even the few indigenous Australian languages that have developed fricatives do not have sibilants.
The voiceless alveolar retracted sibilant (commonly termed the voiceless apico-alveolar sibilant) is a fricative that is articulated with the tongue in a hollow shape, and usually with tip of the tongue (apex) against the alveolar ridge. It is a linguistically unusual sibilant sound that is found most notably in a number of languages in a linguistic area covering northern and central Iberia, and is most well known from its occurrence in the Spanish of this area. In the Middle Ages, it occurred in a wider area, covering Romance languages spoken throughout France, Portugal, and Spain, as well as Old and Middle High German.
There is no single IPA symbol used for this sound. The symbol ⟨s̺⟩ is often used, with a diacritic indicating an apical pronunciation. However, this is potentially problematic in that not all alveolar retracted sibilants are apical (see below), and not all apical alveolar sibilants are retracted. The ad-hoc non-IPA symbols ⟨ṣ⟩ and ⟨S⟩ are often used in the linguistic literature, even when IPA symbols are used for other sounds; ⟨ṣ⟩, however, is a common transcription of the retroflex sibilant [ʂ].
Often, to speakers of languages or dialects that do not have the sound, it is said to have a "whistling" quality, and to sound similar to palato-alveolar [ʃ]. For this reason, when borrowed into such languages or represented with non-Latin characters, it is often replaced with [ʃ]. This occurred, for example, in English borrowings from Old French (e.g. push from pousser, cash from caisse); in Polish borrowings from medieval German (e.g. kosztować from kosten, żur from sūr (contemporary sauer); and in representations of Mozarabic (an extinct medieval Romance language once spoken in southern Spain) in Arabic characters. The similarity between retracted [s̺] and [ʃ] has resulted in many exchanges in Spanish between the sounds, during the medieval period when Spanish had both phonemes. Examples are jabón (formerly xabón) "soap" from Latin sapō, sapōnem, jibia "cuttlefish" (formerly xibia) from Latin sēpia, and tijeras "scissors" (earlier tixeras < medieval tiseras) from Latin cīsōrias (with initial t- due to influence from tōnsor "shaver").
One of the clearest descriptions of this sound is from Obaid: "There is a Castilian s, which is a voiceless, concave, apicoalveolar fricative: The tip of the tongue turned upward forms a narrow opening against the alveoli of the upper incisors. It resembles a faint /ʃ/ and is found throughout much of the northern half of Spain".
Many dialects of Modern Greek have a very similar-sounding sibilant that is pronounced with a laminal articulation.
It occurs as the normal voiceless alveolar sibilant in Astur-Leonese, Castilian Spanish, Catalan, Galician, working-class Glaswegian English, northern European Portuguese, and some Occitan dialects. It also occurs in Basque and Mirandese, where it is opposed to a different voiceless alveolar sibilant, the more common [s]; the same distinction occurs in a few dialects of northeastern Portuguese. Outside this area, it also occurs in a few dialects of Latin American Spanish (e.g. Antioqueño, in Colombia), and in many dialects of Modern Greek (with a laminal articulation).
In medieval times, it occurred in a wider area, including the Romance languages spoken in most or all of France and Iberia (Old Spanish, Galician-Portuguese, Catalan, French, etc.), as well as in the Old and Middle High German of central and southern Germany. In all of these languages, the retracted "apico-alveolar" sibilant was opposed to a non-retracted sibilant much like English [s], and in many of them, both voiceless and voiced versions of both sounds occurred. In general, the retracted "apico-alveolar" variants were written ⟨s⟩ or ⟨ss⟩, while the non-retracted variants were written ⟨z⟩, ⟨c⟩ or ⟨ç⟩. In the Romance languages, the retracted sibilants derived from Latin /s/, /ss/ or /ns/, while the non-retracted sibilants derived from earlier affricates [t͡s] and [d͡z], which in turn derived from palatalized /k/ or /t/. The situation was similar in High German, where the retracted sibilants derived largely from Proto-Germanic /s/, while the non-retracted sibilants derived from instances of Proto-Germanic /t/ that were shifted by the High German sound shift. Minimal pairs were common in all languages. Examples in Middle High German, for example, were wizzen "to know" (Old English witan, cf. "to wit") vs. wissen "known" (Old English wissen), and weiz "white" (Old English wīt) vs. weis "way" (Old English wīs, cf. "-wise").
This distinction has since vanished from most of these languages:
In most dialects of Spanish, the four alveolar sibilants have merged into the non-retracted [s].
In French and most dialects of Portuguese, the four alveolar sibilants have merged into non-retracted [s] and [z], while in European Portuguese, most other Old World Portuguese variants and some recently European-influenced dialects of Brazil all coda [s̺], voiced [z̺] before voiced consonants, was backed to [ɕ], [ʑ], while in most of Brazilian Portuguese this phenomenon is much rarer, being essentially absent in the dialects that conservated the most archaic Portuguese forms and/or had a greater Indigenous and/or non-Portuguese European influence.
In the remaining dialects of Portuguese, found in northern Portugal, they merged into the retracted [s̺] [z̺], or, as in Mirandese (which is, however, not a Portuguese dialect, but belongs to Asturian-Leonese), conservated the mediaeval distinction.
In central and northern Spanish, the non-retracted [s] was fronted to [θ] after merging with non-retracted [z], while the retracted [s̺] remains.
In German, most instances of [s̺] were fronted to [s], but some were backed to become [ʃ] (initially before a consonant, and following /r/; in many modern High German dialects, also non-initially before a consonant), postalveolar as in European and fluminense Portuguese.
Because of the widespread medieval distribution, it has been speculated that retracted [s̺] was the normal pronunciation in spoken Latin. However, it equally well could have been an areal feature inherited from the prehistoric languages of Western Europe, as evidenced by its occurrence in modern Basque.
Comparison with the Spanish apico-alveolar sibilant
The term "voiceless alveolar sibilant" is potentially ambiguous in that it can refer to at least two different sounds. Various languages of northern Iberia (e.g. Astur-Leonese, Catalan, Basque, Galician, Portuguese and Spanish) have a so-called "voiceless apico-alveolar sibilant" which lacks the strong hissing of the [s] described in this article, but rather has a duller, more "grave" sound quality somewhat reminiscent of a voiceless retroflex sibilant. Basque, Mirandese and some Portuguese dialects in northeast Portugal (as well as medieval Spanish and Portuguese in general) have both types of sounds in the same language.
There is no general agreement about what actual feature distinguishes these sounds. Spanish phoneticians normally describe the difference as apical (for the northern Iberian sound) vs. laminal (for the more common sound), but Ladefoged and Maddieson claim that English /s/ can be pronounced apical, which is evidently not the same as the apical sibilant of Iberian Spanish and Basque, In addition, Adams asserts that many dialects of Modern Greek have a laminal sibilant with a sound quality similar to the "apico-alveolar" sibilant of northern Iberia.
Some authors have instead suggested that the difference lies in tongue shape. Adams describes the northern Iberian sibilant as "retracted". Ladefoged and Maddieson appear to characterize the more common hissing variant as grooved, and some phoneticians (e.g. J. Catford) have characterized it as sulcal (which is more or less a synonym of "grooved"), but in both cases there is some doubt about whether all and only the "hissing" sounds in fact have a "grooved" or "sulcal" tongue shape.
Features