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Department of Linguistics

SPH302: Speech Physiology

Phonation

Topics and References

Listed below are the topics covered in this lecture. Where possible, references to books on the reading list are given for each topic.

The textbook reading for this lecture is:-

  • Seikel et al., chapter 6

Additional readings are:-

  1. Clark and Yallop, section 6.6 (2.7 in 1st edn.)
  2. Hardcastle, chapter 4 (esp. pp 83-87)
  3. Daniloff, chapter 6
  4. Perkins et al., chapter 5
  5. Zemlin, chapter 3

Of the above, the Clark and Yallop reference is the briefest and represents mimimum pre-lecture reading. The Seikel and Daniloff references are the most detailed. I would recommend that students read Clark and Yallop before the lecture and either Seikel or Daniloff after the lecture.

Students with an interest in Speech Pathology may wish to read Daniloff (pp 212-217) for a brief summary of pathological vocal qualities. Whilst this material is not examined in this course (it will be covered in depth in the Master of Speech and Language Pathology) it is strongly recommended additional reading for students contemplating a career in speech pathology.

Click here to see a series of movie clips illustrating larynx structure and function.

Click here to see some layngeal anatomy slides.

Vocal Fold Physiology

  1. Dimensions of Vocal Fold Movement
  2. Sub-glottal and Supra-glottal Pressure
  3. Aerodynamic Forces (Bernoulli Effect)
  4. The Glottal Cycle
  5. Mechanical Behaviour of Vocal Folds During a Glottal Cycle
  6. Glottal Vibration and Sound Intensity
  7. Rate of Vibration and Vocal Fold Length, Tension and Thickness
  8. Sex, Age and Vocal Fold Physiology
  9. The Vocal Folds and Phonation Types

Outcomes

Following this lecture, you should:-

  • Understand the dimensions (directions) of vocal fold movement:-
    • Longitudinal changes
      • Changes in length and tension
    • Lateral changes
      • Spreading (adduction and abduction)
      • Medial compression
  • Clearly understand the distinction between:-
    • Vocal fold adduction
    • Vocal fold abduction
  • Clearly understand the distinction between:-
    • Sub-glottal pressure
    • Supra-glottal (oral) pressure
  • Understand that sub-glottal pressure must exceed supra-glottal (oral) pressure for the release of air bursts at the closed glottis.
  • Understand that, for phonation to occur, the force resulting from the difference between sub-glottal and supra-glottal pressure must provide a net force below the vocal folds which exceeds the force which holds the folds together.
  • Understand the elastic forces that resist the opening and assist the closing of the vocal folds during phonation.
  • Understand the Bernoulli effect and the role that it plays in vocal fold closure during a glottal phonatory cycle
  • Understand the Aerodynamic Myoelastic theory of phonation
  • Be familiar with the mechanical behaviour of the vocal folds, especially:-
    • Vertical phase differences (upper and lower edge)
    • Transverse phase differences (spread of glottal opening)
  • Know the relationship between vocal fold medial compression, sub-glottal pressure and sound intensity (and loudness)
  • Know the relationship between intensity and vibration rate
  • Clearly understand the meaning of the term fundamental frequency (F0)
  • Understand the relationship between vibration rate and vocal fold length, tension and thickness (mass)
  • Know how focal fold length and vibration rate varies with sex and age.
  • Understand the differences in average fundamental frequency (F0) as well as the overlap in F0 range between males and females.
  • Understand the vocal fold settings that result in:-
    • Normal voicing ("chest" register)
    • Falsetto
    • Whisper
    • Breathy voice
    • Creak (Glottal "Fry")
  • Understand how hoarseness occurs when the two vocal folds vibrate at different rates.

Following this lecture, you should know the answers to the following questions:-

  • Explain the Aerodynamic Myoelastic theory of phonation.
  • Describe the vocal fold settings and vibratory patterns that result in normal voicing, breathy voice, whisper, creaky voice and falsetto.
  • Describe how fundamental frequency and voice quality are controlled by the larynx.