Acoustics of Consonants Flashcards
Sound Sources
Vowels usually produced with a periodic source of sound
Consonants may use an aperiodic sound source or a combination of periodic and aperiodic sources; never periodic only (vowels)
Vocal Fold Sound Source
Vocal Tract = Resonator
Periodic
Vowels
Dipthongs
SemiVowels
Liquids
Vocal Tract Sound Source
Vocal Tract = Resonator
Aperiodic
Stops
Fricatives
Affricates
Plosives
p/b, t/d, g/k
often called plosive sounds because of burst of noise
Have the greatest degree of constriction to the breath stream
Complete occlusion of the vocal tract
Two simultaneous occlusions are essential
Velopharyngeal closure
Occulsion by the lips or tongue – occlusions are identical to those made by the nasals
Fricatives
f/v, th/th, s/z, sh/zh, h
Produced by compressing a continuous flow of air through a constriction formed by closely approximating two articulators
Four primary places of articulation: Labiodental Linguadental Alveolar Postalveolar
Affricates
ch/dz
English has only two affricates (ch) and (j)
A stop with a fricative release
Acoustically present a combination of stop and fricative features
Silent gaps
Bursts of noise
Extended duration of aperiodicity
Glides
w, y
Nasals
m, n, ng
Liquids
l, r
Vocal Folds & Vocal Tract
Vocal Tract = Resonator
Mixed Periodic and Aperiodic
Voiced Plosives
Voiced Fricatives
Voiced Affricates
Resonant Consonants & SemiVowels
Glides - /w/ “we” (almost resembles [ui]) /j/ “you” (resembles [iu])
Liquids - /r/ “right” /l/ “light”
Vocal tract modifier is the tongue and lips
The vocal tract is relatively open for semivowels; classified as consonants because they are always located next to vocalic nuclei – never /twn/ or /pjk
Nasals
Velopharyngeal port – vocal tract modifier
Also resonant consonants
Three nasal consonants /m/, /n/, /ng/
Levator palatini is the muscle primarily responsible for closing the velopharyngeal port
Pharyngeal wall movement accompanies velopharyngeal closure
Velopharyngeal Port Closure
Maximum velar elevation and backing occur during the articulation of oral consonants – particularly stops and affricates
Leakage of air into the nasal cavity makes it impossible to produce stops and fricatives acceptably
Production of Nasals
Velum is low – VP port is open
Oral cavity is occluded in one of three ways
/m/ lips are brought together
/n/ tip of tongue touches the upper alveolar ridge
/ng/ tongue dorsum touches the posterior part of the hard palate or anterior of soft palate
“some”, “sun”, “sung” – feel the difference in placement
Sound is resonated in the closed oral cavity, the pharyngeal cavity and the nasal cavity
Nasal Acoustics
Acoustically they are weak sounds
Their articulation creates antiresonances- frequency regions in which the amplitudes of the source components are severely attenuated (a filtering affect)
The elongation of the vocal tract caused by the opening of the velopharyngeal port
results in a broader band of frequency response and broadly tuned resonators are more highly damped than narrowly tuned ones
Nonresonant Consonant Acoustic Properties
Fricatives, stops, affricates
Characterized by a much more restricted airflow than for the semivowels and nasals
Acoustically, they display little or nothing of the formant structure observed in the vowels and resonant consonants
Articulators form constrictions and occlusions within the vocal tract that generate aperiodicity (noise)
Most effective resonators for noise are those anterior to the constrictions that produce them
Audible Noise
Makes nonresonant consonants different from resonant consonants and vowels
Resonant consonants and vowels are classified as voiced sounds – without a periodic source the resonant sounds would be inaudible – try producing a voiceless /m/
Noise in the speech signal makes the sounds audible whether or not phonation accompanies their articulation
A single articulation can be used to produce two separate sounds – cognates p/b, t/d, f/v, k/g
Plosive Acoustic Properties
Silent gap – period of silence during which there is no flow of air out of the vocal tract
Noise burst at moment of release – vertical spike on spectrograms – very brief
Speed at which the acoustic signal attains maximum intensity (syllable initial) and falls to minimum intensity (syllable final) – rise time and fall time
Change in first formant frequency after the release of initial stops (rises) and before completion of the closure for final stops (falls
Fricative Acoustic Features
Are continuants – they can be prolonged – unlike stops
Fricative noise originates at the articulatory constriction
f, v, th (voice & voiceless) are low in intensity because there is no resonating cavity anterior to point of constriction
s, z high frequency above 4kHz
Sh farther back in mouth and lower in frequency than s – 2 kHz
Assimilation
a change in the articulation of a speech sound that makes it more like the articulation of the neighboring sound
Coarticulation
two articulators are moving at the same time for different phonemes
Example – “two”
Context Effects
Coarticulation and assimilation are pervasive in running speech
Makes speech transmission rapid and efficient
Suprasegmentals
Prosodic features of speech
Stress
Intonation
Duration
Juncture
Stress
Stress functions as a pointer by indicating which information in an utterance is most important
Intonation
Change in frequency
Pitch pattern
Helpful in expressing differences in attitude
TODAY IS TUESDAY!
TODAY IS TUESDAY?
TODAY IS TUESDAY.
Duration
Sounds possess intrinsic durations
Vowels are of greater duration when they occur before voiced consonants as in “leave” than when they occur before voiceless consonants, as in “leaf”
Juncture
Juncture is related to duration – has to do with how sounds are joined to or separated from each other.
Cues to juncture are acoustic features that help us determine the boundary between two entities.
Juncture is the affiliation of sounds within and between words. Changing the location of a juncture can change meaning: “a+name” and “an-aim” differ in juncture placement
Nitrate v. night rate
amen ask hurt v. a mini skirt
It sprays v. its praise
Acoustics of Stress
Acoustic characteristics associated with heavily stressed syllables
Higher frequency – increased vocal fold tension
Greater duration – more muscular effort in articulatory system
Greater intensity
