Plosives Flashcards
What are Plosives
Stops or plosives are consonant sounds that are formed by completely stopping airflow. Stop sounds can be voiceless or voiced
Give examples of plosives in English
Voiced = /b/ /d/ /g/
Voiceless= /p/ /t/ /k/
Also the glottal stop - complete closure of the glottis. Used in english to omit other stops e. Better (without the /t/)
How are Plosives produced?
The essential articulatory features of stop consonant is a momentary blockage of the vocal tract.
The blockage is formed by an articulatory occlusion, which in English, has one of three sites:
Bilabial
Alveolar
Velar
(there is also a glottal stop, but this is used as an allophone of English consonants)
In other languages stops are produced a variety of places, including palatal uvular and pharengeal.
Uvula [q] and the pharyngeal voiced stop is used in forms of arabic.
Explain the difference between a stop phase and release phase?
Prevocalic stops (the ones found in CV structures) have both a closure phase and a release phase.
- ) Stop phase - The articulatory blockage has a variable durations, usually between 50 and 100 milliseconds. Acoustically the close phase associated with minimum of radiated energy. This is because the vocal tract is abstracted a little or no acoustic energy is produced.
- ) Release phase –Air is released as air pressure is impounded behind the obstruction escapes. The bust is sometimes called transient. Typically the first is no longer than 5 to 40 ms. Is one of the shortest is not the shortest acoustic event it is commonly analysed and speech.
What is the difference in duration between a voiced and voiceless plosive?
Amplitude and duration provide information about consonant voicing but not place of articulation.
A voiceless plosive n English has a typically longer closure duration, a stronger burst, and a longer VOT than a voiced plosive.
Explain Voice onset time and give examples of VOT’s for plosives.
VOT
It is a measure that applies to plosive consonants that are followed by a vowel or other sonorant sound, as in “pay,” “bay,” “play,” “true,” “okay,” “potato.” Voice onset time (VOT) is the time that elapses between the release of the consonant closure and the onset of vocal fold vibration, measured in ms.
In the case of voiceless plosives in most varieties English, this comprises the transient and the aspiration.
In the case of a voiced plosive, it comprises the transient and whatever short stretch of aspiration there may be.
Voiceless plosives have longer VOTs.
When measuring VOT from a speech waveform, the starting point (release of closure) is determined from where the waveform changes from quiescent to transient the end point (the onset of vocal fold vibration) determined from where the waveform becomes periodic.
VOT is the most important feature distinguishing voiced from voiceless plosives in syllable initial position in English. Voiceless plosives have longer VOTs than their voiced counterparts.
VOT is generally 60 -100 msecs for [p]
VOT is generally 0-20 msecs for [b] after stop release.
Explain ‘Period of Silence’/ ‘Stop Gap’ as an acoustic feature of plosives.
Period of silence/stop gap (Appears to the left of the transient) is a region for reduced energy , typically between 10-50ms in duration. The closure interval between the initial vowel and the release burst of the plosive shows a gap in the spectrogram where no energy in voiceless and very low frequency in voiced occurs- this is known as the voice bar.
Explain Transient as an acoustic feature of plosives.
a brief pulse of acoustic energy produced by the initial release of the constriction. When stops are released (except for word final plosives), a transient appears. A transient is rarely more than 20-30 ms in duration.
Explain the interval of aspiration as an acoustic feature of plosives.
occurs between the frication and the onset of voicing.
The spectrum of a stop burst, depends on the phoneme being produced.
Labials have low-frequency dominance.
Alveolars are associated with high energy.
Velars are associated with mid-frequency bursts
Explain frication interval as an acoustic feature of plosives.
a period of turbulence noise generated as the constrictions progressively released. However this does not always occur.
Explain Onset of Voicing as as acoustic feature of plosives.
the initiation of vocal fold vibration for the vowel.
Explain movement of the second and third formants as an acoustic feature of plosives.
These are distinguishable characteristics of the plosives. The movement of the first formant simply mark them as having a stop closure.
Explain the ‘Period of Silence’ in plosives
Voiceless stops in prevocalic positions are characterised by delaying voicing relative to the release of the stop.
For voiceless plosives, the stop gap is virtually silent because the vocal tract is occluded and vocal folds are not vibrating.
For voiced plosives, stop gaps (other than in word-initial position) usually contain low-frequency band called the voice bar. This is a band of energy of the fundamental frequency of vibration.
What is aspiration?
a breathy noise generated as bad passes through the partially closed local folds and into the pharynx.
How does aspiration occur in plosives?
The aspiration closely follows the release burst and is distinguished by the spectrum of noisy energy.
In English, the voiceless plosives have aspirated releases before stressed vowels except when following /s/.
