lecture04 manner fricatives

8/3/2019 Lecture04 Manner Fricatives

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CS 551/651:

Structure of Spoken Language

Lecture 4: Characteristics of Manner of Articulation

John-Paul Hosom

Fall 2008



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Acoustic-Phonetic Features: Manner of Articulation

Approximately 8 manners of articulation:

Name Sub-Types Examples

Vowel vowel, diphthong aa, iy, uw, eh, ow, «

Approximant liquid, glide l, r, w, y

Nasal m, n, ng

Plosive unvoiced, voiced p, t, k, b, d, gFricative unvoiced, voiced f, th, s, sh, v, dh, z, zh

Affricate unvoiced, voiced ch, jh

Aspiration h

Flap dx, nx

Change in manner of articulation usually abrupt and visible;

manner provides much information about location of phonemes.



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Approximants (/l/, /r/, /w/, /y/):

vowel-like properties, but more constriction

/l/ has tongue-tip touching alveolar ridge,

/r/ has tongue tip curled up/back (retroflex), raised and

³bunched´ dorsum, sides of tongue touching molars,

/w/ has tongue back and lips rounded,

/y/ has tongue toward front and very high

glides (/w/, /y/) can be viewed as ³extreme´ production

of a vowel (sometimes called semivowels):

/w/ /uw/

/y/ /iy/



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Approximants (/l/, /r/, /w/, /y/):

movement of tongue slower than other vowel-to-vowel

or consonant-to-vowel transitions, but not as slow as

diphthong movement

sometimes voiceless when following a voiceless

plosive (³play´)

/l/ may have slight discontinuity when tongue makes/breaks

contact with alveolar ridge; other approximants have no

discontinuity



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Nasal (/m/, /n/, /ng/):

produced with velic port open and obstruction in vocal tract sound travels through nasal cavities

these cavities filter speech with both poles (resonances)

and zeros (anti-resonances)

longer pathway causes primary resonance to be low (220-300 Hz)

anti-resonances cause higher frequencies to have lower power

/m/

F1P1

F2 F3

P2

F4 F5

F6

Z1

Z2



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Nasal (/m/, /n/, /ng/):

formant structure obscured by pole-zero pairs

all three English nasals look and sound similar

(place of articulation has little effect on spectrum);

can be distinguished primarily by coarticulatory effects on

adjacent vowel(s).

sometimes very brief duration (³camp´, ³winner´)

occasional confusion with /w/, /l/ (if F3 not visible), and

closure portion of voiced plosives

often sharp discontinuity with adjacent vowel

adjacent vowel may be nasalized



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Plosive (Oral Stop) (/p/, /t/, /k/, /b/, /d/, /g/):

1. closure along vocal tract (lips, alveolar ridge, velum)2. buildup of air pressure behind closure

3. release of closure

4. burst of air

5. possible aspiration following burst

complex process, several changes over brief time span

some context-dependent attributes, some semi-invariant ones

voiced bursts sometimes have ³voice bar´ in low-frequency region, caused by vocal fold vibration with

complete oral and velic closure.

sometimes voice bar is excellent cue; sometimes can

be confused with a nasal



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Plosive (Oral Stop) (/p/, /t/, /k/, /b/, /d/, /g/):

closure and time required to build pressure results in

³silence´ region of spectrum prior to burst

burst airflow is a step function, which becomes similar

to an impulse, which has equal energy at all frequencies

identity of a plosive contained in (at least) three areas:

(1) voice-onset-time (VOT) / duration of aspiration

(2) formant transitions in neighboring vowels/approximants

(3) spectral shape of burst

³voiced´ plosives may not show any real voicing (!)



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Fricative (/f/, /th/, /s/, /sh/, /v/, /dh/, /z/, /zh/):

fricatives produced by forcing air through a constriction

in the mouth

constriction located anywhere from the labiodental region

(/f/, /v/) to palato-alveolar region (/sh/, /zh/)

all English fricatives come in voiced and unvoiced varieties

voicing may not be present in voiced fricatives (!), making

duration an important distinguishing cue (voiced shorter)

the location and type of the constriction create spectral

anti-resonances as well as resonances

the main difference between /s/ and /f/ is in frequencies

above 4000

Hz; telephone-band speech has limit of 4KHz.



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Fricative (/f/, /th/, /s/, /sh/, /v/, /dh/, /z/, /zh/):

Rules for distinguishing between /dh/ and /v/:

/dh/ - formant structure is clearly visible

OR frication is stronger at 5000 Hz and

not so strong at low frequencies

/v/ - formants not visible at location of maximum frication

OR low-frequency energy is as strong as the energy

at 5000 Hz

However, due to the difficulty of distinguishing /dh/ from /v/ and

distinguishing /th/ from /f/, in the spectrogram reading exercises

we will treat them as the same.



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Affricate (/ch/, /jh/):

Affricates are conceptually like diphthongs: two separate

phonemes considered as one

English has two affricates:

/ch/ /t sh/

/jh/ /d zh/

Sometimes cue to affricate is in burst preceding fricative;

in closure between vowel and fricative.

Sometimes cue to affricate is in voicing or duration.



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Aspiration (/h/):

like vowels, except usually no voicing can usually see formant structure

formant patterns similar to surrounding vowel(s)

/ah h aw s/ = ³a house´



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Flaps (/dx/, /nx/):

allophone of /t/, /d/, or /n/ very brief duration; no closure for /dx/

indicated by dip in energy and F2 near 1800 Hz

³write another´

lecture04 manner fricatives

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