To illustrate, let s start with the (excessively simple) phonological system of a made-up language.
Outlandish has three vowels -- /a/, /i/, /u/ -- and every Outlandish syllable must contain one of these. There are seven consonants that can start syllables --- /p/, /t/, /k/, /b/, /d/, /g/, /s/ -- and a syllable may also lack an initial consonant. Syllables may optionally end with the consonant /n/.
Outlandish thus has 48 possible syllables: the syllable onset has 8 options (/p/, /t/, /k/, /b/, /d/, /g/, /s/ or nothing), the syllable nucleus has three options (/a/, /i/, /u/), and the syllable coda has two options (/n/ or nothing), and 8 x 3 x 2 = 48.
Outlandish words are made up of from 1 to 4 syllables. In consequence, there are 5,421,360 possible Outlandish words -- 48x48x48x48 + 48x48x48 + 48x48 + 48 = 5,421,360.
Thus the phonological elements of Outlandish, as we have described them, are /i/, /a/, /u/, /p/, /t/, /k/, /b/, /d/, /g/, /s/, /n/. The phonological structures of Outlandish include the notions of syllable, onset, nucleus, and coda.
Some examples of Outlandish words might /kanpiuta/ "electronic calculator", /kaa/ "automobile", /pi/ "climbing annual vine with edible seeds", /bata/ "emulsion of milkfat, water and air".
In giving the phonological encoding of these words, we ve omitted the structure, because it is unambiguously recoverable from the string of elements. For instance, /kanpiuta/ must be a four-syllable word whose first syllable contains the onset /k/, the nucleus /a/, and the coda /n/, etc.
Real languages all have more complex phonological systems than our made-up language Outlandish does. However, it remains true that phonological structures are mostly recoverable from strings of phonological elements, and therefore can be omitted for convenience in writing. In this way of writing down phonological representations as strings of letter-like phonological elements, the "letters" are usually called phonemes.
From phonemes to mouth gestures and noises (and back again)
We ve exemplified half of the situation: the "Outlandish" example explains what kind of thing a phonological system is, and how the pronunciation of words can be specified by "spelling" them in phonological terms.
What about the phonetic interpretation of words, that is, the interpretation of phonemic strings in terms of mouth gestures and the accompanying noises? How does that work?
In these notes, we ll give only a very basic overview. This topic is covered in more detail in Ling 330 (Introduction to Phonetics and Phonology). Ling 520 (graduate Introduction to Phonetics) is a laboratory courses that goes into considerably more detail, and is open to interested undergraduates with appropriate background.
Basic sound production in the vocal tract: buzz, hiss and pop
There are three basic modes of sound production in the human vocal tract that play a role in speech: the buzz of vibrating vocal cords, the hiss of air pushed past a constriction, and the pop of a closure released.
Laryngeal buzz
The larynx is a rather complex little structure of cartilage, muscle and connective tissue, sitting on top of the trachea. It is what lies behind your "adam s apple." The original role of the larynx is to seal off the airway, in order to prevent aspiration of food or liquid, and also to permit the thorax to be pressurized to provide a more rigid framework for heavy lifting and pushing.
Part of the airway-sealing system in the larynx is a pair of muscular flaps, the vocal cords or vocal folds, which can be brought together to form a seal, or moved apart to permit free motion of air in and out of the lungs. When any elastic seal is not quite strong enough to resist the pressurized air it restricts, the result is an erratic release of the pressure through the seal, creating a sound. Some homely examples are the Bronx cheer, where the leaky seal is provided by the lips; the belch, where the opening of the esophagus provides the leaky seal; or the rude noises made by grade school boys with their hands under their armpits.
The mechanism of this sound production is very simple and general: the air pressure forces an opening, through which air begins to flow; the flow of air generates a so-called Bernoulli force at right angles to the flow, which combines with the elasticity of the tissue to close the opening again; and then the cycle repeats, as air pressure again forces an opening. In many such sounds, the pattern of opening and closing is irregular, producing a belch-like sound without a clear pitch. However, if the circumstances are right, a regular oscillation can be set up, giving a periodic sound that we perceive as having a pitch. Many animals have developed their larynges so as to be able to produce particularly loud sounds, often with a clear pitch that they are able to vary for expressive purposes.
The hiss of turbulent flow
Another source of sound in the vocal tract -- for humans and for other animals -- is the hiss generated when a volume of air is forced through a passage that is too small to permit it to flow smoothly. The result is turbulence, a complex pattern of swirls and eddies at a wide range of spatial and temporal scales. We hear this turbulent flow as some sort of hiss.
In the vocal tract, turbulent flow can be created at many points of constrictions. For instance, the lower teeth can be pressed against the upper lip -- if air is forced past this constriction, it makes the sound associated with the letter (and IPA symbol) [f].
When this kind of turbulent flow is used in speech, phoneticians call it frication, and sounds that involve frication are called fricatives.
The pop of closure and release
When a constriction somewhere in the vocal tract is complete, so that air can t get past it as the speaker continues to breath out, pressure is built up behind the constriction. If the constriction is abruptly released, the sudden release of pressure creates a sort of a pop. When this kind of closure and release is used as a speech sound, phoneticians call it a stop (focusing on the closure) or a plosive (focusing on the release).
As with frication, a plosive constriction can be made anywhere along the vocal tract, from the lips to the larynx. However, it is difficult to make a firm enough seal in the pharyngeal region to make a stop, although a narrow fricative constriction in the pharynx is possible.
Sound shaping by the vocal tract: vowel color and nasality
Between the larynx and the world at large is about 15 centimeters of throat and mouth. This passageway acts as an acoustic resonator, enhancing some frequencies and attenuating others. The properties of this resonator depend on the position of the tongue and lips, and also on whether the velum is lowered so as to open a side passage to the nasal cavities. Some examples of shapes in a computer model of the human vocal tract, the corresponding resonance patterns, and the sounds that result when a laryngeal buzz in shaped by these resonances, can be found here.
Different positions of the tongue and lips make the difference between one vowel sound and another. As you can easily determine for yourself by experiment, you can combine any vowel sound with any pitch -- or with a whisper, which is a hiss created by turbulent flow at the vocal folds.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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