CS 551/651: Structure of Spoken Language Lecture 3: Phonetic Symbols and Physiology of Speech...
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Transcript of CS 551/651: Structure of Spoken Language Lecture 3: Phonetic Symbols and Physiology of Speech...
CS 551/651:Structure of Spoken Language
Lecture 3: Phonetic Symbols andPhysiology of Speech Production
John-Paul HosomFall 2010
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
Phonetic Symbols: the IPA
Tongue tipor bladetouchingupper lip
Produced With tip of tongue,e.g. Spanish/r/
Phonetic Symbols: the IPA
Other IPA symbols…
Phonetic Symbols: the IPA
Examples:
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
nasal tract(hard) palate
oral tract
velum (soft palate)
velic port
tongue
tongue tippharynx
glottis(vocal folds and
space between vocal cords)
vocal folds (larynx)= vocal cords
alveolar ridge
lips
teeth
The Speech Production Apparatus (from Olive, p. 23)
Acoustic Phonetics: Anatomy
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 trachea.
Acoustic Phonetics: Anatomy
Phonation (from Daniloff, chapter 6):
Phonation is “conversion of potential energy of compressed airinto kinetic energy of acoustic vibration.” For voiced speech:
1. Buildup of Pressure:air pressure from the lungs pushes against closed vocal foldsso that Psubglottal > Poral; buildup continues untiluntil 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, causingacoustic shock wave moving along vocal tract
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
Acoustic Phonetics: Anatomy
Implications:
1. vocal folds do not open and close because of separate muscle movements
2. opening and closing is automatic as long as the resting positionof 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)
quietbreathing
forcedinhalation
normalphonation
whisper
Acoustic Phonetics: Anatomy
The cycle of glottal vibration (from Daniloff, p. 171)
1. folds at rest 2. muscle contraction
3. increase in pressure
4. forcing folds apart
5. “explosion” open
6. acoustic shockwave
8. folds close, goto step (3)
7. rebound toward closure
Acoustic Phonetics: Anatomy
The cycle of glottal vibration (from Pickett, p. 50)
closure to opening, 0 to 2.1 msec
opening to closure, 2.4 to 4.5 msec
(F0 = 222 Hz)
Acoustic Phonetics: Anatomy
Types of phonation (from Daniloff, p. 174)
voiceless, whisper, breathy voiced, creak, glottal stop
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’spitch increases:
Vcglide.mov
http://www.youtube.com/watch?v=ajbcJiYhFKY
Acoustic Phonetics: Anatomy
Some cool (gross?) videos:
Acoustic Phonetics: Anatomy
The effects of nasalization on vowels (from Pickett, p. 71)
Figure 4-17. An example of theeffects of vowel nasalization onthe vowel spectrum. The spectrumenvelopes of a normal [a] and a heavilynasalized [a] were plotted… The firstthree formants are labeled in the normal vowel. In the nasalized vowel,there are three local reductions inspectrum level, indicated by “z’s”;these are the result of the additionof anti-resonant zeros to the vocaltract response, due to a wide-openvelar 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 poleand its corresponding zero, as well as their frequency locations.
1. The presence of a pole-zero pair increases the apparent bandwidth of the neighboring formants.
2. The presence of spectral zero below F1 tends to make the location of F1 appear slightly higher (50-100 Hz) than it normally would
3. If the zero is higher in frequency than its corresponding pole, the net effect is to reduce the amplitude of higher frequencies