Definition
Plosive (also known as
stops,
mutes, occlusives,
explosives) sounds are formed by the air being completely blocked in the mouth and then suddenly released. A plosive is a consonant articulation with the following characteristics:
• One articulator is moved against another, or two articulators are moved against each other, so as to form a stricture that allows no air escape from the vocal tract. The stricture is, then, total.
• After the stricture has been formed and air has been compressed (held) behind it, it is released; that is, air is allowed to escape.
• If the air behind the stricture is still under pressure when the plosive is released, it is probable that the escape of air will produce noise loud enough to be heard. This noise is called plosion.
• There may be voicing during part or all of the plosive articulation.
Classification
We have 6 Plosive sounds in English: /p/b/t/d/k/g/. The Plosive consonant sounds are generally described on three bases:
1. Manner of articulation : The manner of articulation is concerned with airflow i.e. the paths it takes and the degree to which it is impeded by vocal tract constrictions. In other words, manner of articulation describes how the sound is produced. In the articulation of the plosive sounds, four phases can be distinguished:
(i) Closing phase: In this stage the two organs move very close to one another and create a complete closure or blockade.
(ii) Hold/occlusion/compression phase: In this stage the air is held behind the closure.
(iii) Release or burst: The two organs move away from one another (closure is opened) and the air goes out and the released airflow produces a sudden impulse causing an audible sound (hence the name plosive).
(iv) Post Release phase: The articulators are now further apart, and the air pressure at the site of the obstruction has fallen so that the speech sound is no longer a burst with energy in all frequencies, but bands of aspiration which are more narrowly concentrated and which move toward the formant values in the next phoneme.
2. Place of articulation: The place of articulation refers to where the sound is produced. The plosives have different places of articulation. For example, /p/ and /b/ are bilabial since the lips are pressed together; /t/ and /d/ are alveolar since the tongue blade is pressed against the alveolar ridge; the plosives /k/ and /g/ are velar sounds since the back of the tongue is pressed against the area where the hard palate ends and the soft palate begins (velum).
3. Voicing: Voicing refers to whether or not the vocal cords are vibrating. The plosives /p/t/k/ are always voiceless. On the other hand, /b/d/g/ are sometimes fully voiced and sometimes voiceless. On the basis of breathe force these 6 plosives can be divided into two groups:
(i) Fortis
(ii) Lenis
Some phoneticians opine that the degree of breath and muscular effort involved in the articulation between the groups
voiceless and
voiced are not the same. According to them voiceless (/p/t/k/) English consonants tend to be articulated with a strong degree of breath and muscular effort. They produce strong or forceful vibration in the vocal cord. For their strong nature they are called
fortis. Voiced (/b/d/g/) English consonants tend to be articulated with a weak degree of breath and muscular effort. They produce less vibration in the vocal cord since they need less force. For their weak nature they are called
lenis. Thus the terms fortis and lenis allow one to describe in more precise terms than 'voiced and unvoiced' the articulation of English consonants. They refer to a bundle of articulatory features which have different distributions in different languages. The most important of those is perhaps
aspiration, a type of sound which could be pronounce with an extra puff of air for which we may hair a “h” like sound.
Distribution
The following discussion gives a detailed description of the distribution of the plosive sounds. All six plosives can occur
initially,
medially and
finally.
1. Initial Position: The closing phase for /p/ t/ k/ and /b/d/g/ takes place silently. During the hold phase of there is no voicing in /p/t/k/, but in /b/d/g/, on the other hand, we normally very little voicing. The release phase of /p/t/k/ is followed by an audible plosion, that is, a burst of noise. There is then, in the post-release phase, a period during which air escapes through the vocal folds, making a sound like “h”. This is called aspiration. For example: pin, tin, kin. The release of /b/d/g/, on the other hand, is followed by weak plosion.
2. Medial position: The pronunciation of /p/t/k/ and /b/d/g/ in medial position depends to some extent on whether the syllables preceding and following the plosive are stressed (both depend on the context). In general we can say that a medial plosive may have the characteristics either of final or initial plosives.
3. Final Position: The final /b/d/g/ have little voicing. /p/t/k/ are voiceless. The plosion for both is non audible. The difference is that the vowels preceding /p/t/k/ are shorter than the ones preceding /b/g/d/
References
Roach, Peter.
English Phonetics and Phonology: A self-contained, comprehensive pronunciation course.
3rd ed. Cambridge: CUP, 2000.
Varshney, Dr. R.L.
An Introduction of Linguistics & Phonetics. Dhaka: BOC, n.d. 87-90.
Yule, George.
The Study of Language. 2
nd ed.
Cambridge: CUP, 1996. 40-47