1. Structure of Spoken Language
CS 551/651:
Structure of Spoken Language
Lecture 3: Phonetic Symbols and Physiology of Speech Production
John-Paul Hosom
Fall 2010

2. Phonetic Symbols: the IPA The International Phonetic Alphabet (IPA)
(reproduced compliments of the International Phonetic Association, Department of Linguistics,
University of Victoria, Victoria, British Columbia, Canada)

3. Phonetic Symbols: the IPA

4. Phonetic Symbols: the IPA
Produced
With tip of
tongue,
e.g. Spanish
/r/
Tongue tip
or blade
touching
upper lip

5. Phonetic Symbols: the IPA
Other IPA symbols…

6. Phonetic Symbols: the IPA
Examples:

7. Phonetic Symbols: Worldbet
An ASCII representation of IPA, developed by Hieronymous (AT&T)

8. Phonetic Symbols: ARPAbet, TIMITbet, OGIbet
ASCII representation of English used in TIMIT corpus.

9. Phonetic Symbols: SAMPA
An ASCII representation for multiple (European) languages

10. Acoustic Phonetics: Anatomy
nasal tract
(hard) palate
velic port
oral tract
alveolar ridge
velum (soft palate)
lips
tongue
teeth
pharynx
glottis (vocal folds and space between vocal cords)
tongue tip
vocal folds (larynx)
= vocal cords
The Speech Production Apparatus (from Olive, p. 23)

11. Acoustic Phonetics: Anatomy
Breathing and Speech (from Daniloff, chapter 5):
Duration of expiration in soft speech is 2.4 to 3.5 seconds; maximum value (singers, orators) is 15 to 20 seconds without distress.
Louder voice requires inhaling more deeply after expiration; also deeper inhalation if followed by longer speech.
More intense voicing requires greater lung pressure.
Lung pressure relatively constant throughout an utterance.
Emphasis in speech: greater tenseness in vocal folds yielding higher F0; greater lung pressure increases airflow (energy).

12. Acoustic Phonetics: Anatomy
the false vocal folds narrow the
glottis during swallowing, preventing
pieces of food from getting into the
trachea.

13. Acoustic Phonetics: Anatomy
Phonation (from Daniloff, chapter 6):
Phonation is “conversion of potential energy of compressed air
into kinetic energy of acoustic vibration.”
For voiced speech:
1. Buildup of Pressure:
air pressure from the lungs pushes against closed vocal folds
so that Psubglottal > Poral; buildup continues until
until Psubglottal – Poral > elastic recoil force of vocal folds
2. Release:
vocal folds forced open by pressure difference;
burst of compressed air hits air in vocal tract, causing
acoustic shock wave moving along vocal tract

14. Acoustic Phonetics: Anatomy
Phonation
3. Closure of Vocal Folds, two factors:
(a) force of elastic recoil in vocal folds
Vocal folds have elastic or recoil force proportional to
the degree of change from the resting position.
(b) Bernoulli Effect
(i) energy at location of vocal folds is conserved: E = KE + PE
(ii) increase in KE causes decrease in PE
(iii) PE corresponds to pressure of air
(iv) drop in pressure causes walls of glottis to be
drawn closer together
Summary: air burst causes high rate of airflow, causes
drop in pressure, causes folds to be pulled together

15. Acoustic Phonetics: Anatomy
Implications:
vocal folds do not open and close because of separate muscle
movements
2. opening and closing is automatic as long as the resting position
of the vocal folds is (near) closure, and there is sufficient
pressure buildup below vocal folds
3. Factors governing vocal fold vibration:
(a) position of vocal folds (degree of closeness between folds)
(b) elasticity of vocal folds, depending on position and
degree of tension
(c) degree of pressure drop across vocal folds

16. Acoustic Phonetics: Anatomy
Types of phonation (from Daniloff, p. 194)
quiet
breathing
forced
inhalation
normal
phonation
whisper

17. Acoustic Phonetics: Anatomy
The cycle of glottal vibration (from Daniloff, p. 171)
1. folds at rest
2. muscle
contraction
5. “explosion”
open
6. acoustic
shockwave
3. increase in
pressure
4. forcing folds
apart
7. rebound toward
closure
8. folds close,
goto step (3)

18. Acoustic Phonetics: Anatomy
The cycle of glottal vibration (from Pickett, p. 50)
opening to closure, 2.4 to 4.5 msec
closure to opening, 0 to 2.1 msec
(F0 = 222 Hz)

19. Acoustic Phonetics: Anatomy
Types of phonation (from Daniloff, p. 174)
voiceless, whisper, breathy
voiced, creak, glottal stop

20. Acoustic Phonetics: Anatomy
Some cool (gross?) videos:
Video of fiberoptic stroboscopy exam:
(ignore the background music!)
And here’s another video from
showing the vibration of the vocal folds as a person’s
pitch increases:

21. Acoustic Phonetics: Anatomy
The effects of nasalization on vowels (from Pickett, p. 71)
Figure An example of the
effects of vowel nasalization on
the vowel spectrum. The spectrum
envelopes of a normal [a] and a heavily
nasalized [a] were plotted… The first
three formants are labeled in the
normal vowel. In the nasalized vowel,
there are three local reductions in
spectrum level, indicated by “z’s”;
these are the result of the addition
of anti-resonant zeros to the vocal
tract response, due to a wide-open
velar port.

22. Acoustic Phonetics: Anatomy
The effects of nasalization on vowels (from Pickett, p. 71)
Coupling of the oral and nasal tract introduces pole-zero pairs
(resonances & anti-resonances, occurring in pairs) in the spectrum.
The amount of coupling affects the spacing between each pole
and its corresponding zero, as well as their frequency locations.
The presence of a pole-zero pair increases the apparent bandwidth of the neighboring formants.
The presence of spectral zero below F1 tends to make the location of F1 appear slightly higher ( Hz) than it normally would
If the zero is higher in frequency than its corresponding pole, the net effect is to reduce the amplitude of higher frequencies