Pharynx

6 Key excerpts on "Pharynx"

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  eBook - ePub

  The Speech Chain

  The Physics And Biology Of Spoken Language

  • Dr. Peter B. Denes, Dr. Elliot N. Pinson(Authors)
  • 2016(Publication Date)
  • Hauraki Publishing

    (Publisher)

  Much more research has to be done before we can fully explain how the characteristics of the sounds produced depend on the shape of the vocal tract. Even where the process is fairly well understood, complicated mathematics are needed for the calculation of the formants. As a result, much of what we know about the formants of speech sounds is obtained simply by examining the sounds produced when the vocal tract has a given shape, rather than by explaining how these formants came about. Examination of the acoustic characteristics of speech waves has not only produced more information about formants, but has brought to light other important features of speech waves. These results will be described in Chapter 7.

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  We have seen how the energy for speech is provided by the air stream from the lungs and how vocal cord vibration generates an audible buzz. Let us go on to see how the quality of this buzz is changed by the configuration of the vocal tract. A cross-sectional view of the vocal tract is shown in Fig. 4.7. The vocal tract extends from the glottis to the lips—by way of the Pharynx and mouth—with a side branch into the nasal passages.

  The Pharynx is the part of the vocal tract nearest the glottis. It is a tube connecting the larynx with the mouth and the nose. At its lower end, the Pharynx meets the larynx and the esophagus and, at its wider upper end, joins with the back of the mouth and the nose, as shown in Fig. 4.8. We have known for some time that its shape and size are changed when swallowing, either by moving the tongue back, or the larynx up, or by contracting the pharyngeal walls. Only recently, however, has it been noticed that such changes take place during speech. These changes can be seen clearly in the vocal tract outlines shown in Fig. 4.9. Very little is known about the pharyngeal changes we make for distinguishing one speech sound from another. As a result, we shall not have much to say about the Pharynx later in this chapter, when we describe the movements of the vocal organs for articulating English speech sounds.

     

  The nasal cavity (see Fig. 4.7), extending from the Pharynx to the nostrils, is about four inches long. It is divided into two sections by the septum , a central partition that runs along the entire length of the cavity. Ridges and folds in the cavity’s walls break up some segments of the nasal air passages into intricately shaped channels. At the back of the nose—and also lower down in the Pharynx—are the tonsils (see Fig. 4.7). They occasionally grow large enough to influence the air flow from the lungs and, when they do, they add the characteristic “adenoidal” quality to the voice. The sensory endings of the nerve concerned with smell are also located in the nose. The nasal cavities can be isolated from the Pharynx and the back of the mouth by raising the soft palate

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  eBook - ePub

  Phonetics

  Transcription, Production, Acoustics, and Perception

  • Henning Reetz, Allard Jongman(Authors)
  • 2011(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  2

  Articulatory Phonetics

  An important component of phonetics is the description of sounds. One mode of description is articulatory; that is, it involves an articulatory description of how speech sounds are produced. First of all, the production of any kind of sound requires a source of energy. For speech this energy source is the flow of air. For most sounds of the world’s languages, this airflow is generated by the lungs, which are described in detail in Section 5.1. Air flows from the lungs through the trachea (windpipe) and then through the larynx (voice box), where the vocal folds are located. The larynx and its role in the complex process of voice formation are discussed in detail in Section 5.2. Finally, the physiological details of the upper part of the speaking apparatus, namely the Pharynx (throat), oral tract (mouth), and nasal tract (nose) are presented in Section 5.3. In this chapter, aspects of the speaking apparatus that are easy to observe will be introduced, including phonation at the larynx and articulation in the vocal tract. This description will help to explain terms used for phonetic transcription (Chapter 3).

  2.1 Phonation at the Larynx

  The larynx (voice box) is located at the bottom of the Pharynx (throat) on top of the trachea (windpipe) and consists of cartilage, muscle, ligament, and tissue. For some speakers, the larynx is visible as the Adam’s apple, moving up and down during swallowing and speaking. It is not this movement that is central for speech production but the operation of two small muscular folds inside the larynx. These are known as the vocal folds (or vocal cords) and airflow generated by the lungs must pass through them. The vocal folds can be either apart, close together, or tightly closed. When they are apart (as in normal breathing), air travels through without much obstruction. When they are tightly closed, no air passes through, which prevents, for example, food from entering the trachea. When they are close together, the airstream from the lungs will make them vibrate. This vibration is known as voicing or phonation. It is important to note that voiced sounds such as vowels and many consonants are produced with vocal fold vibration (vocal folds close together) while voiceless sounds are produced without vocal fold vibration (vocal folds apart). The presence and absence of vocal fold vibration can be determined by placing your finger loosely on your Adam’s apple and prolonging the sound at the beginning of a word like

  z ip

  (“zzzzzzzz”). This is a voiced consonant produced with vocal fold vibration and you should be able to feel this vibration with your finger. The beginning of a word like sip

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  eBook - ePub

  The Sounds of Language

  An Introduction to Phonetics and Phonology

  • Elizabeth C. Zsiga(Author)
  • 2012(Publication Date)
  • Wiley-Blackwell

    (Publisher)
• People throughout recorded history have been interested in describing the structure and function of the organs of speech, but this was difficult to do with precision until the advent of tools such as the X-ray, sonography, and MRI that allow us to “see” inside the body. In this chapter we recall the basics of how each technology works, with its strengths and limitations.
• There are no parts of the body used exclusively for speech. All the parts of the vocal tract have another, non-speech use.
• Speech is the movement of air made audible. Air can be made audible by making a narrow turbulent channel, by building up pressure behind a constriction, or by making the body of air resonate.
• The vocal tract can be divided into three sub-sections: sub-laryngeal, laryngeal, and supra-laryngeal.
• Most speech sounds are made with air exiting the lungs: the pulmonic egressive airstream.
• The larynx is made up (in part) of the cricoid cartilage, thyroid cartilage, arytenoid cartilages, and vocal folds. This chapter shows us the approximate shape and position of each. The primary linguistic function of the larynx is the control of vocal fold vibration (pitch and voicing).
• The supralayrngeal tract can be divided into active and passive articulators. The active articulators are the lower lip, tongue front (tip and blade), tongue body, and tongue root. The passive articulators are the upper lip, upper teeth, alveolar ridge, post-alveolar region, hard palate, soft palate (velum), uvula, and pharyngeal wall.
• In addition to its status as a passive articulator, the velum is a valve that opens and closes to regulate airflow between oral and nasal cavities.