Voiceless Postalveolar Fricative
The voiceless postalveolar fricative is a consonantal sound common to many of the world's spoken languages. For English speakers, this sound is most recognizable as the "sh" heard in words like "ship." In the International Phonetic Alphabet (IPA), this sound is represented by the symbol ⟨ ʃ ⟩, known as the esh.
While often referred to as a palato-alveolar fricative, the IPA specifically uses the term "voiceless postalveolar fricative" to describe this sibilant sound. It is distinct from the voiceless postalveolar non-sibilant fricative, which possesses significantly different perceptual qualities.
Key Facts
- IPA Symbol: ⟨ ʃ ⟩ (esh).
- English Example: The "sh" in "sheep."
- Manner: Sibilant fricative (high-frequency turbulence).
- Place: Postalveolar (behind the alveolar ridge).
- Phonation: Voiceless (no vocal cord vibration).
- Airstream: Pulmonic (powered by the lungs).
Technical Features and Articulation
To understand how the voiceless postalveolar fricative is produced, it is helpful to break down its phonetic features:
Manner of Articulation
This sound is a sibilant, a subclass of fricatives and affricates. Sibilants are characterized by the production of high-frequency turbulence, created by directing a stream of air against the teeth.
Place of Articulation
It is postalveolar, meaning the tip or blade of the tongue is positioned just behind the alveolar ridge (the bony ridge behind the upper teeth).
Phonation and Airstream
The sound is voiceless, meaning the vocal cords do not vibrate during its production. It is an oral consonant, as air escapes only through the mouth, and a median consonant, meaning the airstream is directed down the midline of the tongue. The mechanism is pulmonic, utilizing the intercostal and abdominal muscles to push air from the lungs.
Global Occurrence and Notation
The voiceless postalveolar fricative appears in a vast array of languages. While the IPA uses ⟨ ʃ ⟩, other notations exist. For example, the symbol ⟨ š ⟩ (an s with a caron or háček) is used in Americanist phonetic notation, the Uralic Phonetic Alphabet, and various Slavic orthographies, originating from the Czech orthography of Jan Hus.
| Language | Word | IPA | Meaning |
|---|---|---|---|
| English | sheep | [ˈʃiːp] | sheep |
| French | cher | [ʃɛʁ] | expensive |
| Arabic | شَمْس | [ʃams] | sun |
| German | schön | [ʃøːn] | beautiful |
| Spanish (Rioplatense) | ayer | [äˈʃe̞ɾ] | yesterday |
| Turkish | güneş | [ɟyˈne̞ʃ] | sun |
Related Postalveolar Sounds
Voiceless Postalveolar Non-Sibilant Fricative
Distinct from the sibilant [ ʃ ], the voiceless postalveolar non-sibilant fricative (transcribed as ⟨ ɹ̝̠̊ ⟩ or ⟨ ɹ̠̊˔ ⟩) is produced without the grooved tongue or high-frequency turbulence of a sibilant. An example occurs in Received Pronunciation English in the word "crew" [kɹ̝̠̊ʊu̯], where the /r/ is partially devoiced after a fortis plosive.
Voiceless Postalveolar Approximant
Some scholars identify a voiceless postalveolar approximant ⟨ ɹ̠̊ ⟩, which is distinct from the fricative. This can be found in the Changki dialect of the Ao language and certain dialects of Bengali.
Frequently Asked Questions
What is the difference between [ ʃ ] and [ ʂ ]?
While [ ʃ ] is a palato-alveolar fricative, [ ʂ ] is an apical retroflex fricative. For example, the sound denoted by ⟨ ш ⟩ in Russian is actually an apical retroflex fricative [ ʂ ], though it is often transcribed as [ ʃ ].
How is the 'esh' symbol different from an integral sign?
Although they look similar, the IPA symbol ⟨ ʃ ⟩ (esh) was introduced by Isaac Pitman for phonetic use and is distinct from the mathematical integral symbol ⟨ ∫ ⟩.
Is the 'sh' sound always the same in every language?
No. While many languages use [ ʃ ], some may produce it with simultaneous labialization [ ʃʷ ] (common in English and French) or use different tongue shapes, such as the apical realization found in some Italian dialects.
What does 'voiceless' mean in phonetics?
Voiceless means the sound is produced without the vibration of the vocal cords. In some languages, the cords are actively separated to ensure the sound remains voiceless.