Supralaryngeal Physiology
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Introduction
• Source-filter theory
–Source = generates sound (larynx)
–Filter = sound modified (vocal tract)
• Vocal tract–Filter for all vowels and consonants
–Serves as source of noise for
consonants
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Noise Generation: Source
• All consonants include an element of noise (except
semi-vowels)
• Consonant that is voiced= Noise added to the voice
generated at Glottal Source
• Consonant that is voiceless= Characterized entirely
by noise
• Narrowing of vocal tract causes resistance to cause
noise (usually in upper vocal tract)
– /h/ is an exception- noise caused at the glottis
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Oral Pressure
• Two functions of vocal tract:
– Serves as a filter for all consonants & vowels
– Serves as a source of noise for most consonants
• Prerequisite for noise:
– Build pressure behind constriction or occlusion
• Intraoral air pressure (requires velopharyngeal
competence)
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Turbulent Noise
• The noise element of consonants produced
by fricatives is the result of turbulence.
– Hiss of steam
– Occurs when air channel is constricted enough
to disrupt smooth flow of air
– Turbulence if the other type of consonant noise
(bursts & turbulence)
– Place of articulation distinguishes fricatives
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Places of Articulation
K-G-NG
M-W-P-B
SH-ZHL-CH-J-R
TH T-D-S-Z-N
F-V
H
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Bursts of Noise
• Burst, a puff of air
• Air stream is stopped by tongue or lips
(plosive or stop)
• Progress of stop:
– Closure (tongue, lips)-Block air stream
– Pressure builds behind stoppage
– Brief gap of silence
– Stoppage is released (can be aspirated)
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Closure
Stoppage
Release
Transition
Airstream
Airstream
Stoppage
Transition
Silence
Plosive
Burst
Vowel
Typical Plosive Production
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Vowels
• Vowels studied using lateral head x-rays
– liquid-barium
• Early description of vowels– tongue height
– tongue advancement
– Russell & Leiberman- criticize theory (can’t
distinguish /e/ and /e / by tongue contour only)
– Must include:
• lip configuration
• height of larynx
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Vowels
• Four features to describe vowels:
1) Tongue position
2) Lip configuration
3) Velar position
4) Width and length of pharynx
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Vowels
• Characteristics:
–all voiced
–Sonorants (nonobstruent)
• Produced with relatively open vocal tract
• Voicing is dominant feature
• No blockage of airstream
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Vowels
• Binary classification:
–1) high/ low
–2) front/ back
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Location of Vocal Tract Constrictions for Vowels
LOOT
BEAT
BIT
BAIT
BAT
BOTTLE
LOOT
FOOT
OMIT
WALK
LOT
LOT
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Glides & Liquids
• Referred to as semi-vowels or consonants
– Greater degree of vocal tract constriction than
vowels
1) Glides: articulatory movement connecting two
vocalic type sounds
– /j/: Tongue position for /i/ and rapid movement
to next vowel
• more open vocal tract
• opposite of dipthong
• rapid movement important for distinction (two
adjacent vowels)
• narrow constriction = turbulent flow
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Glides & Liquids
– /w/: same articulation shape as /u/, but
more lip rounding and rapid articulation
into following vowels (similar to
dipthongs but faster articulation)
2) Liquids:
– /r/: produced with some lip rounding
• context dependent
• usually assumes place of cluster its in (/sr/,
/br/)
• palatal retroflex position
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Glides & Liquids
– /l/:
lateral sound
• tongue tip touches alveolar ridge
• openings on either side of tongue
• context sensitive
• differs greatly on position in utterance
• All glides have low flow (about 1/2
of vowels)
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Entire class of Semi-Vowels
• Assume vocal tract is slightly more
closed than for vowels
• Intraoral pressure slightly above
atmospheric (about 1 cm/H2O)
• Translaryngeal flow will be less than
vowels
• Lowest flow of any phoneme
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Dipthongs
• Have flow similar to vowels (large)
• two vowel positions connected by slow
tongue movement
• speed of articulation slower than glides
• articulatory posture different than
producing separate vowels (ex. /aI/ not
the same as /a/, /I/)
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Consonants
• 1) Stops:
–Characterized by:
•plosives (bilabial, lingu-alveolar,
velar)
•voicing features (ex. /t/ vs. /d/)
•most complex set of sounds
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Stops (plosives)
• Articulatory movement characteristics:
– articulatory gesture towards intended
articulatory place
– contact of tongue or lips shutting off oral
cavity
– brief maintenance of oral occlusion (60140 msec)
– release of occlusion
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Stops
• 4 Specifications factors :
1) Closure interval (articulatory), build
up of Po (aerodynamic), 60-140
msecs
2) Release of constriction or burst
(articulatory), Po drops to Patm
(aerodynamic), 2-12 msecs
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Stops
3) Expanding constriction (articulatory), turbulent
flow & oral flow decs. (aerodynamic), 20 msecs
(bilabials), 25-30 (lingua-alveolar), 35-40
(dorsals)
4) Closing vocal folds
– folds open during closure interval
– folds move to closed position for following
vowel (same time as release)- 60-100 msecs
– aspiration noise created (high flow & narrow
fold opening)
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Stops: Aerodynamics
• Consonant in medial position
/ipi/:
–upon contact Po rises steeply
–cessation of flow
–occlusion = stoppage of flow
–after occlusion is released:
• Po falls steeply
• rapid burst of airflow
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Stops: Aerodynamics
• Steps following the occlusive stage
(voiceless):
–no flow corresponding to occlusion
–turbulent flow after release of
articulators
• laminar flow becomes turbulent (narrow
constriction)
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Stops: Aerodynamics
• Burst- release of stop
• Frication- turbulent flow between expanding artic.
constriction (“noise”)
• Aspiration- vf’s moving from open to closed; air moving
past closing folds causes turbulence
2-12 msec
Burst
20-60 msec
Frication
100 msec
Aspiration
VOT
First
vibration
of folds
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Stops: Aerodynamics
Summary:
3 Stage Sequence of Stop Release
Occlusion (no flow)
Expanding constriction (turbulence)
Narrow glottal chink (aspiration)
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Stops: VOT
• Voiceless stop:
– VOT= burst, frication and aspiration without
vocal fold vibration
• Voiced stops: have shorter VOT, why?
– no aspiration interval in voiced stops
– just burst & frication
– frication interval may also be shorter Aspiration
does not occur during VF vibration
• flow not high enough because folds are moving &
interrupting flow
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Stops: Tense vs. Lax
• Voiced stops:
– lax because of pharyngeal expansion
– walls of vocal tract are very compliant
– pressure increases, displace walls easier,
thus decrease in pressure overall
• Voiceless stops:
– tense; no pharyngeal wall expansion
– pressure increased overall; less compliance
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Fricatives
• Continuant consonants:
– vocal tract constriction much greater than
semi-vowels but no complete occlusion
– created by narrow constriction somewhere in
vocal tract
– voiceless fricatives have higher Po than
voiced
– voiced fricatives less pressure than voiced
stops
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Fricatives
• voiceless: source supraglottal
• voiced: dual source (larynx and supraglottal)
• Aerodynamics:
– 1) very high Po
– 2) pressure held longer than plosives (cleft
palate)
– 3) highest airflow (range- 100-500 cc/sec)
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Affricates
• Composed of stop and fricative
– brief occlusion interval (pressure high)
– occlusion shorter than for stops (cluster
duration shorter than single form)
– Long frication interval (turbulent flow &
slowly expanding constriction)
– Flow and pressure in-between stops and
fricatives
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Nasals
• Oralization gesture= velum pulled up
touching pharyngeal walls
– seals oral cavity; build up Po
– necessary for vowels too (lesser extent)
• Nasalization gesture= velum lowered
– need resonance in nasal cavity
– Po becomes negligible relative to Patm
– Vn and Pn increase
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Co-Articulation
• Articulatory movements for one phone
which are carried over into the
production of previous or subsequent
phones, but which do not affect the
primary place of articulation.
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Co-Articulation
• Alot of overlap in running speech
• Theory: Speech series of beads
(representing phonemes) presented
in series: Not true
• Overtax muscular system
• Therefore, co-articulation occurs
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Co-Articulation
• Kent, Carney & Severeid– sagital X-ray motion
– sutured metal pellets to velum & tongue
– ex. /Intend/- forward and backward co-artic.
• after nasal /n/ velum moves well before closure for
the /t/
• closure starts at 300-500 msec. before /t/
• Right-to-left co-articulation: articulation gesture for
upcoming phoneme occurs earlier in time
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Co-Articulation
• Carryover: Left to right influences in which
earlier phonetic activity replaces
forthcoming phonetic activity
• Anticipatory: Right to left influences in
which forthcoming phonetic activity
replaces earlier phonetic activity
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Co-Articulation
• Anticipatory: /stu/
– liprounding on /s/
– /s/ has no specifications for lip
configuration
• Carryover : /no/
– vowel will be slightly nasalized because
of lowered velum in production of /n/
– slower movements include VP opening &
lip rounding
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Organization of Speech Production
• Isolated production (ideal)
• CNS remembers appropriate ‘set’ of
muscular activities to produce given
phoneme
• there can be certain variations from ideal and
still make sound appropriate perceptually
• Hypothesis of planning utterances
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Organization of Speech Production
• Selection of craniofacial target forms
associated with phonological unit
• selection of time program for speech
– ex. /s/ in the words ‘speed’, ‘speedier’ &
‘speediest’ becomes shorter for each
progression
– evidence /s/ not independent of duration's
of succeeding elements
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Organization of Speech Production
• Organization of speech planning is roughly
the length of a clause: 5-9 syllables in length
• Overall duration of these utterances is
roughly constant regardless of # of syllables
in a clause
• Therefore, the same phoneme changes in
duration depending on what sounds surround
it.
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Organization of Speech Production
• Humans speak at close to maximum rates
– 6-7 syllables per second
– 10-14 sounds per second
– We do fast movements with slow articulators by
overlapping articulatory movements
• ex. difference in tongue position for “nine” and
“ninth”
– in ninth the tongue is fronted to adjust for the upcoming
“th”
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Quantal Theory of Articulation
• Certain point where undershoot or
articulators for a phoneme will exceed the
range of phoneme class
• Undershoot= failure of articulators to reach
their craniofacial form
• Range of vocal tract configuration for prod.
• Outside range of variability= change in
acoustic output
• Boundary creates quantum change
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Quantal Theory of Articulation
• explains co-articulation with certain
variability allowed
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