Articulation and Resonance
• Vocal tract as resonating body and sound
source.
• Acoustic theory of vowel production.
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Basic Anatomy Review
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Basic Anatomy Review
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Basic Anatomy Review
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Vocal tract as resonating body
and sound source.
• Phonation sound source is VF vibration.
• Vocal tract is 1/4 wavelength resonator
– 17 cm long in the average adult male.
– Open end is mouth and closed end is vocal
folds.
– There are a number of secondary 1/4
wavelength resonators due to changes in tube
diameter.
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Acoustic (Source) Theory of
Vowel Production
• Source
• Filter
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Source
• Source of all vowels is vocal fold vibration
• Source creates fo and harmonics
• Harmonics are attenuated with an increase
in frequency
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Filter
• Filters modify the intensity of harmonics
• Remember… The vocal tract a 17 cm 1/4
WL resonator and has a primary resonant
frequency of 500 Hz & secondary resonant
frequencies at 1500 and 2500 Hz.
• Transfer function shows effects of vocal
tract resonance.
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• Insert figure 4.62
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Interaction between
source and filter
• In real world there are additional resonances
which interact in vowel production.
• Every time you change vocal tract
configuration you change resonant peaks.
• You also have radiation effect which results
in 6 dB/octave increase in high frequencies.
• All these factors interact to produce a
vowel.
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Interaction between
source and filter
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• In above example resonant peaks are labeled F1,
F2, & F3. These are known as formant
frequencies.
• Formant frequencies can be displayed on a
Spectrogram which shows frequency on ordinate
and time on abscissa.
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Speech Production
English Speech Sounds
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Vowels & Diphthongs
Semivowels
Nasals
Stops
Fricatives
Affricates
Sound Influence
Suprasegmentals
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Vowels
• Vowels classified by tongue and mandible
position.
• High front vowels
• Low back vowels
• High back vowels
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High Front Vowels
• Include
• Tongue placed high and forward in vocal
tact
• Mandible somewhat closed
• High oral constriction
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Low back vowels
• Tongue constriction occurring to the rear of
vocal tract
• Mandible opening is wide. Pharyngeal
constriction is greater than other vowels.
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High back vowels
• Tongue constriction in back of vocal tract.
• Mandible is somewhat closed.
• Lips are somewhat protruded.
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Vowel Quadrilateral
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Vowels may be displayed
showing formant frequencies
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Spectrograms of Some Vowels
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Diphthongs
• Vowels of changing resonance
• On next slide we have examples of
diphthongs. Notice how F1 and F2
transitions between first and second vowel.
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Diphthongs (continued)
• Peterson and Lehiste call shorter diphthongs
Tense Monophthongs. These include
diphthongs found in “bay and boat”
• Longer diphthongs are those found in “find,
bout, boy”
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Semivowel production
• Four semivowels /w, j, r, l/
• Similar to vowels because they are highly
resonant.
• Considered to be consonants because they
function in language to release the vowel or
diphthong. E.g., “swim” is possible “swm”
is not.
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Semivowels (continued)
• Two classes of semivowels…
– Glides /j, w/
– Liquids /l, r/
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Semivowels (continued)
• Glides…
– are so named because the formants glide to and
from adjacent vowels. Very similar to a
diphthong except it has a much faster transition.
– In terms of place of production …
• /j/ is considered a palatal glide
• /w/ is labial glide
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Semivowels (continued)
• Liquids…
– Involve placing tongue tip either close to or
near the alveolar ridge.
– /r/ - tongue tip does not touch alveolar ridge
while airflow passes centrally through a
grooved tongue.
– Some dialects omit /r/
– /w/ for /r/ substitution is common since /w/ is
easier to produce.
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Semivowels (continued)
• /l/ - tongue tip touches alveolar ridge while
airflow passes laterally.
• In initial position /l/ is produced as speaker
releases the tongue.
• In the final position it is of long duration.
• /l/ of long duration are sometimes referred
to as a “dark /l/”
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Nasals
• Include /m/, /n/, and /ng/
• Anti-resonances … need to discuss prior to actual
nasal production.
– Opposite of resonance. Attenuates a range of
frequencies.
– All nasals have anti-resonances which are a result of a
cul-de-sac formed by closed vocal tract.
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Nasals (continued)
• Place of articulation has a direct effect on size of
cul-de-sac and anti-resonant frequency.
• The place of artic and anti-resonant frequency for
each nasal is as follows . . .
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Nasals (continued)
• Other characteristics include …
– All air passes through nasal cavity.
– Because air passes through nasal cavity (longer
pathway than oral tract) you have a lower
resonant frequency than non-nasals.
– Nasals have relatively low intensity, especially
for upper formants.
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