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Flashcards in Acoustics of Consonants Deck (28)
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1

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)

2

Vocal Fold Sound Source

Vocal Tract = Resonator

Periodic

Vowels
Dipthongs
SemiVowels
Liquids

3

Vocal Tract Sound Source

Vocal Tract = Resonator

Aperiodic

Stops
Fricatives
Affricates

4

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

5

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

6

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

7

Glides

w, y

8

Nasals

m, n, ng

9

Liquids

l, r

10

Vocal Folds & Vocal Tract

Vocal Tract = Resonator

Mixed Periodic and Aperiodic

Voiced Plosives
Voiced Fricatives
Voiced Affricates

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

Assimilation

a change in the articulation of a speech sound that makes it more like the articulation of the neighboring sound

21

Coarticulation

two articulators are moving at the same time for different phonemes
Example – “two”


22

Context Effects

Coarticulation and assimilation are pervasive in running speech

Makes speech transmission rapid and efficient

23

Suprasegmentals

Prosodic features of speech

Stress
Intonation
Duration
Juncture

24

Stress

Stress functions as a pointer by indicating which information in an utterance is most important

25

Intonation

Change in frequency

Pitch pattern

Helpful in expressing differences in attitude
TODAY IS TUESDAY!
TODAY IS TUESDAY?
TODAY IS TUESDAY.

26

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”

27

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

28

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