Speech Sound Waves

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Speech Sound Waves The Voice

• LING 3330 Phonetics and Phonology Spring 2009

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Critical thinking problem of the day

• In the string of letters below, can you cross out
  all the unnecessary letters so that a logical
  sentence remains?
• ALALTLHOEGUICNANL
• ESCEENSTSEANRCYEL
• REETMTAEIRSNS

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Critical thinking problem of the day

• In the string of letters below, can you cross out
  all the unnecessary letters so that a logical
  sentence remains?
• ALALTLHOEGUICNANL
• ESCEENSTSEANRCYE
• LREETMTAEIRSNS

ALALTLHOEGUICNANL ESCEENSTSEANRCYE LREETMTAEI
RSNS
ALALTLHOEGUICNANL ESCEENSTSEANRCYE LREETMTAEI
RSNS
ALALTLHOEGUICNANL ESCEENSTSEANRCYE LREETMTAEI
RSNS
ALALTLHOEGUICNANL ESCEENSTSEANRCYE LREETMTAEI
RSNS
ALALTLHOEGUICNANL ESCEENSTSEANRCYE LREETMTAEI
RSNS
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REVIEW from last time

• First thing What should you expect to get out of
  this class?
• What you put into it!
• To think critically about observed evidence to
  make hypothesis about unobserved reality
• The International Phonetics Alphabet
• Why would we need to know it?

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REVIEW from last time

• The International Phonetics Alphabet
• Why would we need to noa it?
• So you dont have to
• waste brain cells
• (and ink) using letters
• that dont make
• any noise

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Introduction to sound waves

• But first a little story
• Old McDonald had a farm and on his farm he had a
  large barn with a cow, a horse, a chicken, a cat,
  and a mouse.
• One day, he decided to set up an experiment in
  his barnyard to see if he could keep track of
  exactly where his farm animals were in the barn.
  
• To do this, he set up a large fan at the very
  back of the barn.
• As the fan blows air through the barn, it hits an
  animal, bounces off and eventually leaves the
  barn through the front door.

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Introduction to sound waves

• But first a little story
• In the barnyard, he has set up a receving dish
  that captures the air waves an sends a signal
  inside his house to his 486Dx hand-me-down
  computer from his kids
• (you see Farmer McDonald didnt know how to use a
  web cam and didnt have usb anyway.)
• Lo and behold the experiment works!

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Introduction to sound waves

• But first a little story
• He now knows his cow is at the back left, his
  horse is near the entrance, the chicken is in the
  front right corner, and the cat is about to
  pounce on the mouse in the middle of the barn!
• BUT HOW???

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Introduction to sound waves

• HOW it works. Consider the case of human speech
  communication
• we have the three main branches of Phonetics
• Articulatory (which is?)
• the identification classification of individual
  sounds
• Acoustic (which is?)
• the analysis and measurement of sound waves
• Auditory (which is?)
• the ear and how sound is perceived

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Introduction to sound waves

• When we say sounds several things are implied.
• some thing is produced and
• some thing is heard
• It is first of all the sensation produced by
  stimulating the organs of hearing

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Introduction to sound waves

• Articulatory

Acoustic
Auditory
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http//darkwing.uoregon.edu/guion/411notes/1Intro
.pdf 6
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Auditory Phonetics Perception

• we see here the anatomy of the human ear
• Inside is the eardrum which is moved by air
  pushed down the ear canal

http//www.uptodate.com/patients/content/images/pe
di_pix/Normal_ear_anatomy.jpg
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Auditory Phonetics Perception

• As the sound hits the eardrum it causes the
  membrane to vibrate.
• As the eardrum moves it sends a signal to the
  cochlea via 3 small bones
• Liquid in the cochlea stimulates nerve endings
  sending messages to the brain

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Auditory Phonetics Perception

• The brain interprets the messages from the nerves
  as ___________(what)?
• SOUND!!!
• BUT how does it get there in the first place?

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Introduction to Acoustics wave forms

• Sound is produced when something vibrates in a
  medium that can carry the vibration.
• In most cases the medium which with we are most
  familiar is
• AIR.
• However other mediums also carry vibration waves
  solids and liquids also can carry vibration.

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Introduction to Acoustics wave forms

• When objects move rapidly in air they affect the
  air molecules in their vicinity to the point that
  those molecules cause a disturbance next to them
  and a wave is formed (similar to throwing a
  stone in water).

http//www.varmintal.com/tuning-fork2a.gif
http//www.glenbrook.k12.il.us/gbssci/phys/mmedia/
waves/tfl.gif
http//www.kettering.edu/drussell/Demos/rad2/mdq.
html
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Introduction to Acoustics wave forms

• As seen in these two images the wave form travels
  through the air in pulses as the air pressure
  fluctuates higher and lower than the ambient air
  causing the vibration.

http//www.glenbrook.k12.il.us/gbssci/phys/Class/s
ound/gsl.gif http//www.glenbrook.k12.il.us/gbssc
i/phys/Class/sound/eds.gif
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Introduction to Acoustics wave forms
http//www.physicsclassroom.com/Class/sound/u11l1c
.cfm
http//www.kettering.edu/drussell/Demos/waves-int
ro/waves-intro.html
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Introduction to Acoustics wave forms

• 1 Hertz 1 vibration/second
• (or 1 cycle/sec)
• Sounds are measuredamplitude (dB)/frequency
  (Hz)/ duration (sec)

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Introduction to Acoustics wave forms

• The ears of a human (and other animals) are
  sensitive detectors capable of detecting the
  fluctuations in air pressure which impinge upon
  the eardrumthe human ear is capable of detecting
  sound waves with a wide range of frequencies,
  ranging between approximately 20 Hz to 20,000 Hz.
  
• Any sound with a frequency below the audible
  range of hearing (i.e., lt 20 Hz) is known as an
  infrasound
• Any sound with a frequency above the audible
  range of hearing (i.e., gt 20,000 Hz) is known as
  an ultrasound.

http//www.physicsclassroom.com/Class/sound/u11l2a
.cfm
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Introduction to Acoustics wave forms

• Dogs can detect frequencies as low as
  approximately 50 Hz and as high as 45,000 Hz.
• Cats can detect frequencies as low as
  approximately 45 Hz and as high as 85 000 Hz.
• Bats, being nocturnal creature, must rely on
  sound echolocation for navigation and hunting.
  They can detect frequencies as high as 120,000
  Hz.
• Dolphins can detect frequencies as high as
  200,000 Hz.
• While dogs, cats, bats, and dolphins have an
  unusual ability to detect ultrasound, an elephant
  possesses the unusual ability to detect
  infrasound, having an audible range from
  approximately 5 Hz to approximately 10,000 Hz.

http//www.physicsclassroom.com/Class/sound/u11l2a
.cfm
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Introduction to Acoustics wave forms

• The sensation of a frequencies is commonly
  referred to as the pitch of a sound. A high pitch
  sound corresponds to a high frequency sound wave
  and a low pitch sound corresponds to a low
  frequency sound wave.

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Introduction to Acoustics wave forms

• Humans can also make many other sounds with their
  speech organs than what are employed as discrete
  units (or meaningful units) of sounds within
  language.
• e.g. raspberry, whistling, screaming, etc.
• NOTE While these are not language they can
  still be communication.

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Introduction to Acoustics wave forms

• Very quickly lets explore what makes a sound wave
  of speech
• the wave forms weve been seeing are simple sine
  waves (the oscillations are regular and periodic
  they go up and down the same amount over the
  whole wave)
• Speech wave forms are complex and they are
  aperiodic.

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Introduction to Acoustics wave forms

• Speech wave forms are complex
• the complex waveform is the result of
  simultaneous presence of many component
  frequencies

http//www.victor-victrola.com/COMPLEXSINE.gif
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Introduction to speech organ articulation

• Human speech sound waves have other features that
  we will return to after looking at the process of
  how we generate the wave in the first place.
• There is a source and a filter.
• the source would be?
• The larynx/vocal cords/glottis
• what do you think is the filter?
• throat, mouth, sinus cavities, etc.

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Speech organs articulation

• The vocal tract
• The oral cavity, nasal cavity, pharynx, and
  larynx
• Vocal Folds
• (previously thought to be cords) two folds of
  tissue with embedded muscle and ligaments found
  inside the larynx. Attached at the back to the
  arytenoids cartilages and in the front to the
  inner surface of the thyroid cartilage. Their
  vibration is the source of the periodic energy
  for human speech sounds.

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Speech organs articulation

• Larynx
• Cartilage connective tissue at the lower end of
  the vocal tract and above the windpipe,
  containing the vocal folds
• Glottis
• The space between the vocal folds

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Speech organs articulation

• 2 main divisions of the Vocal tract system

http//www.haskins.yale.edu/featured/heads/MMSP/gr
aphics/fig1.gif
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Speech organs articulation

• Showing the 4 main components of the speech
  mechanism

http//www.haskins.yale.edu/featured/heads/MMSP/gr
aphics/fig1.gif
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Speech organs articulation

• Glottal wave (formed by vibration of the vocal
  folds due to subglottal pressure)
• Bernoulli effect
• The rapid rise in airflow when the cords open (5)
• results in a drop in pressure and consequent
  suction effect which tends to draw the cords back
  into the closed position (6-8)

http//www.ncvs.org/ncvs/tutorials/voiceprod/image
s/glot_wave.jpg
http//www.phon.ox.ac.uk/jcoleman/mucosa_wave.GIF
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Speech organs articulation

• Glottal wave (formed by vibration of the vocal
  folds due to subglottal pressure)
• This vibration in the larynx is heard as pitch.
  It is measured in Hz and it called the
  fundamental frequency (or F0) average around
  120Hz adult male 220 Hz adult female.
• (80Hz is considered low range of a bass voice
  while a soprano can reach as high as 1170Hz)

http//www.ncvs.org/ncvs/tutorials/voiceprod/image
s/glot_wave.jpg
http//www.phon.ox.ac.uk/jcoleman/mucosa_wave.GIF
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Speech organs articulation

• Larynx and epiglottis
• Ball Rahilly 99 p. 9

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Speech organs articulation

• Supralaryngal or Supraglottal vocal tract
• Oral Cavity
• Nasal Cavity

Ladefoged 2006
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Speech organs articulation

• Oral Cavity
• lips
• teeth
• jaw/mandible
• alveolar ridge
• tongue
• tip,
• blade,
• body/dorsum,
• root
• hard palate
• velum/soft palate
• uvula
• pharynx
• epiglottis

Hayes 2009
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Speech organs articulation

• Oral Cavity
• lips
• teeth
• jaw/mandible
• alveolar ridge
• tongue
• tip,
• blade,
• body/dorsum,
• root
• hard palate
• velum/soft palate
• uvula
• pharynx
• epiglottis

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Speech organs articulation

• Harmonics (based on the glottal wave)
• These different harmonics have different
  frequencies and amplitudes

http//www.glenbrook.k12.il.us/gbssci/phys/Class/s
ound/u11l4d.html
http//www.physicsclassroom.com/Class/waves/u10l4d
.cfm
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Speech organs articulation

• Harmonics (based on the glottal wave arrows show
  H1-4)
• These different harmonics have different
  frequencies and amplitudes (also called roll-off)

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Speech organs articulation

• Formants (based on the shape of the vocal tract
  filter the articulators)

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Speech organs articulation
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Speech organs articulation

• then it all fits together to give us speech
  segments (or phonemes)

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• A short video
• while watching this consider the pressure source,
  the sound source, and the filter aspect that we
  just discussed.
• BreathingWithPhilJones_Sydney.mpg

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Conclusion

• Any questions?
• What do you understand better now?
• What do you still not understand or is worse?
• There will be a short quiz on Wed over aspects
  and components of speech production (Hayes p.
  2-4), and IPA (no oral transcription).

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Introduction to Acoustics wave forms