Speech Acoustics Chapter 6: Consonants, VOT, and Assimilation

What are the four sound sources of speech?

Voiced source, turbulent source, transient source, combined source.

What characterizes a voiced source?

Vocal fold vibration; includes vowels, nasals, glides, and liquids.

What is a turbulent source?

Turbulent airflow through narrow constriction in the vocal tract, producing an aperiodic, hissing quality.

What defines a transient source?

Abrupt changes in airflow due to a release of air pressure built-up behind a constriction in the vocal tract; includes stops like /p, t, k/.

What are combined sources in speech?

Sources that include combinations of voiced, turbulent, and transient elements.

What are semivowels?

Glides and liquids that have similar articulations and acoustic features to vowels.

What is the primary acoustic cue for semivowels?

Formant transition.

How are glides produced?

Glides occur only before a vocalic nucleus, with /j/ produced close to /i/ and /w/ produced close to /u/.

What distinguishes lateral /l/ from retroflex /r/?

Lateral /l/ has no significant change in F3, while retroflex /r/ shows a falling F3.

What are stop consonants (plosives)?

Nonresonant consonants articulated with the greatest degree of obstruction to the airstream, causing momentary cessation of airflow.

What happens during the release of a stop consonant?

A transient burst of noise occurs as the constriction is released.

What is the role of velopharyngeal closure in stop production?

It elevates the velum to prevent airflow through the nasal cavity.

What is a noise burst in stop consonants?

A brief spike of sound following the silent gap, more prominent for voiceless stops.

How does formant transition occur in stop production?

F1 rises rapidly after the release of initial stops and falls rapidly before completion of closure for final stops.

What are the acoustic features of labial stops?

Weak and low frequency burst energy; F1, F2, and F3 frequencies increase for the following vowel.

What distinguishes alveolar stops from other stops?

They have strong burst energy at high frequencies around 3000 Hz.

What is the burst energy characteristic of velar stops?

Strong burst energy at mid frequencies; F2 and F3 begin close together and separate during the transition.

What is the significance of formant transitions in stop consonants?

They indicate the place of articulation and help differentiate between different stop sounds.

What is the typical duration of a noise burst for stop consonants?

Very brief, typically between 10 to 35 ms.

What happens to the formant frequencies during the transition from /b/ to /d/?

F2 and F3 frequencies decrease for the following vowel.

How does the place of articulation affect burst energy in stops?

Different places of articulation produce varying frequencies of burst energy.

What is a syllabic consonant?

A consonant that can function as a syllable nucleus, such as liquids.

What is the acoustic feature of voiced stops?

Presence of a low-intensity harmonic, realized as a voice bar.

What is Voice Onset Time (VOT)?

The interval between the release of a stop consonant and the onset of voicing.

What are the three types of VOT categories for English stops?

Short lag, long lag, and prevoicing.

How is voicing determined in stop consonants?

By the Voice Onset Time (VOT) in initial position.

What are the voicing contrasts in English stop consonants?

/p/, /t/, /k/ (voiceless) vs. /b/, /d/, /g/ (voiced).

What are fricatives?

Nonresonant consonants articulated with the airstream passing through a constriction in the vocal tract.

What are the places of articulation for English fricatives?

Labiodental, linguadental, alveolar, and postalveolar.

What distinguishes voiced fricatives from voiceless fricatives?

Voiced fricatives have a voice bar, while voiceless fricatives do not.

What is the difference between sibilants and non-sibilants?

Sibilants have a hissing quality (e.g., /s/, /z/), while non-sibilants do not (e.g., /f/, /v/).

What is an affricate?

A consonant that begins as a stop and releases as a fricative.

What are nasals in speech?

Resonant consonants articulated with the velum lowered and the nasal cavity open.

What is assimilation in phonetics?

The alteration of a sound due to the influence of neighboring sounds.

What is coarticulation?

When two articulators move simultaneously for different phonemes, creating temporal overlap.

What is the frequency range for the nasal murmur of /m/?

500 to 1,500 Hz.

What is the frequency range for the nasal murmur of /n/?

Around 2,000 to 3,000 Hz.

How does nasalization affect sound?

It causes attenuation of higher formants relative to neighboring vowels.

What is the role of the velum in producing nasals?

The velum is lowered to allow airflow through the nasal cavity.

What characterizes the sound of voiceless fricatives?

They are characterized by the presence of noise intervals (frication).

What is the difference between complete and partial assimilation?

Complete assimilation affects place, manner, and voicing, while partial assimilation only affects one aspect.

What is the significance of the place of articulation in fricatives?

It affects the intensity of noise in different frequency ranges.

What is the acoustic property of alveolar fricatives compared to postalveolar fricatives?

Alveolar fricatives have intense noise in higher frequencies than postalveolar fricatives.

What is the typical onset characteristic of voiceless fricatives?

Typically gradual onset.

What is the function of the oral cavity in producing nasals?

The oral cavity is occluded, resonating sound in the nasal cavity.

What is the effect of a lateral lisp?

It is produced with the airstream passing over the sides of the tongue.

What does the term 'nonresonant consonants' refer to?

Consonants that are articulated with a constriction in the vocal tract, such as stops and fricatives.