The Articulation and Acoustics of Consonants

Speech ScienceFall 2009

Oct 26, 2009

ConsonantsResonant ConsonantsThey are produced in a similar way as vowels

i.e., filtering the complex wave produced at the glottis in the resonating cavities of the vocal tract.

The Semivowels glides (/w/ and /j/) and liquids (/r/ and /l/)

The Nasals /m/, /n/, and [ŋ] Mining [maInIŋ]

ConsonantsNasalsVelopharyngeal portOpening to the nasal

cavity from the pharyngeal and oral cavities.

This must be opened for the three nasal sounds.

It is closed by elevating and backing the velum.

ConsonantsNonresonant Consonants: They are produced by articulators forming

constrictions and occlusions within the vocal tract that generate aperiodic noise as air passes through them.

Much more restricted airflow than that for the semivowels and nasals.

Acoustically, unlike vowels and resonant consonants, they display no formant structure.

The Fricatives, The Stops, The Affricates

ConsonantsThe Stops:Airflow in vocal tract is blocked completely

for a brief period of time and then the built up air pressure is released suddenly.

/p/, /t/, /k/

Other name for these sounds is “plosives” http://home.hib.no/al/engelsk/seksjon/SOFF-MASTE

R/Stops.htm

ConsonantsThe FricativesAn aperiodic sound is

produced by forcing the air stream through an articulatory constriction for relatively extended period of time.

This will cause a continuous source of noise that is longer in duration than the transient noise bursts of the stops.

http://home.hib.no/al/engelsk/seksjon/SOFF-MASTER/Fricatives.htm

ConsonantsThe AffricatesAn affricate is simply a stop with a fricative

release[tʃ] and [dʒ]

Consonants: Types of Sound Sources

Acoustics of the SemivowelsThere are similarities between vowels and

liquids and glidesVocal tract is relatively open for the

semivowels.Acoustically, they are characterized by the

formants.

Acoustics of the Semivowels /j/For the production of /j/,

tongue blade must approximate the palate at a position close to that for a high front vowel

/aja/The first formant frequency

decreasesSecond formant frequency

increasesMovement of the tongue and

lips change vocal tract shape from starting position (similar to /i/) to next vowel sound.

Acoustics of the Semivowels/w/Starting position is characterized by a high

back tongue position and protruded lips (similar to /u/).

The articulators then move rapidly to following vowel.

Acoustics of the Semivowels/r/ and /l/They are produced in syllable-initial position

by raising the tongue toward the alveolar ridge.

Tongue tip position and configuration creates distinction between these two sounds

Acoustics of the SemivowelsFor /r/, F3 frequency

plunges below the F3 frequencies of neighboring vowels

For /l/, it doesn’t depart from them significantly.

Acoustics of the Semivowels/l/ and /r/ in their final positionFinal /l/ is articulated with the dorsum of the

tongue raised somewhat toward the velum (e.g., cool, full)

For final /r/, loses its consonantal quality and simply colors whatever vowel it follows. (e.g., car and hear

Some speakers may elevate the tongue dorsum toward the palate.

Acoustics of the NasalsThe addition of nasal cavity creates vocal

tract a longer and larger resonator.Therefore, it naturally responds to lower

frequencies.Acoustic result is called “murmur”This murmur or formant lies within the 200-

300 Hz range Acoustically, nasal consonants are weak due

to antiresonances within the vocal tract.

Acoustics of the NasalsThe antiresonances are frequency regions in

which the amplitudes of the source components are severely attenuated.

Consonants are articulated with more constriction or occlusions than vowels.

Resonances and antiresonances can cancel each other if those frequencies are close enough or one formant may appear as two.

Acoustics of the NasalsThe frequency ranges

for the antiresonances associated with nasal sounds vary with place of articulation.

For /m/, antiresonance is in the range of 500-1500 Hz.

For /n/, the range is between 2000-3000 Hz and for / /, it is above 3000 Hz.