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CS 551/651: Structure of Spoken Language Lecture 3: Phonetic Symbols and Physiology of Speech Production John-Paul Hosom Fall 2008. More Formant Data…. (source unknown). Effects of Coarticulation. Phonetic Symbols: the IPA The International Phonetic Alphabet (IPA)

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CS 551/651:

Structure of Spoken Language

Lecture 3: Phonetic Symbols andPhysiology of Speech Production

John-Paul Hosom

Fall 2008

More Formant Data…

(source unknown)

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)

Phonetic Symbols: the IPA


With tip of


e.g. Spanish


Tongue tip

or blade


upper lip

Phonetic Symbols: the IPA

Other IPA symbols…

Phonetic Symbols: Worldbet

An ASCII representation of IPA, developed by Hieronymous (AT&T)

Phonetic Symbols: ARPAbet, TIMITbet, OGIbet

ASCII representation of English used in TIMIT corpus.

Phonetic Symbols: SAMPA

An ASCII representation for multiple (European) languages

Acoustic Phonetics: Anatomy

nasal tract

(hard) palate

velic port

oral tract

alveolar ridge

velum (soft palate)





tongue tip

glottis(vocal folds and space between vocal cords)

vocal folds (larynx)

= vocal cords

The Speech Production Apparatus(from Olive, p. 23)

  • 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).

Acoustic Phonetics: Anatomy

the false vocal folds narrow the

glottis during swallowing, preventing

pieces of food from getting into the


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

Acoustic Phonetics: Anatomy


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

  • 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

Acoustic Phonetics: Anatomy

Types of phonation (from Daniloff, p. 194)








Acoustic Phonetics: Anatomy

The cycle of glottal vibration (from Daniloff, p. 171)

1. folds at rest

2. muscle


5. “explosion”


6. acoustic


3. increase in


4. forcing folds


7. rebound toward


8. folds close,

goto step (3)

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)

Acoustic Phonetics: Anatomy

Types of phonation (from Daniloff, p. 174)

voiced, creak, glottal stop

voiceless, whisper, breathy

Acoustic Phonetics: Anatomy

Some cool (gross?) videos:

Video of fiberoptic stroboscopy exam:

(ignore the background music!)

And here’s another video from http://www.voiceinfo.org/

showing the vibration of the vocal folds as a person’s

pitch increases:


Acoustic Phonetics: Anatomy

The effects of nasalization on vowels (from Pickett, p. 71)

Figure 4-17. 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.

  • 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 (50-100 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