Discuss the description and classification of Consonants and Vowels.
Producing a consonant involves making the vocal tract narrower at some location than it usually is. We call this narrowing a constriction. Which consonant you’re pronouncing depends on where in the vocal tract the constriction is and how narrow it is. It also depends on a few other things, such as whether the vocal folds are vibrating and whether air is flowing through the nose.
We classify consonants along three major dimensions:
- place of articulation
- manner of articulation
The place of articulation dimension specifies where in the vocal tract the constriction is. The voicing parameter specifies whether the vocal folds are vibrating. The manner of articulation dimesion is essentially everything else: how narrow the constriction is, whether air is flowing through the nose, and whether the tongue is dropped down on one side.
For example, for the sound [d]:
Place of articulation = alveolar. (The narrowing of the vocal tract involves the tongue tip and the alveolar ridge.)
Manner of articulation = oral stop. (The narrowing is complete — the tongue is completely blocking off airflow through the mouth. There is also no airflow through the nose.)
Voicing = voiced. (The vocal folds are vibrating.)
The vocal folds may be held against each other at just the right tension so that the air flowing past them from the lungs will cause them to vibrate against each other. We call this process voicing. Sounds which are made with vocal fold vibration are said to be voiced. Sounds made without vocal fold vibration are said to be voiceless.
There are several pairs of sounds in English which differ only in voicing — that is, the two sounds have identical places and manners of articulation, but one has vocal fold vibration and the other doesn’t. The [θ] of thigh and the [ð] of thy are one such pair.
The other sounds of English do not come in voiced/voiceless pairs. [h] is voicess, and has no voiced counterpart. The other English consonants are all voiced: [ɹ], [l], [w], [j], [m], [n], and [ŋ]. This does not mean that it is physically impossible to say a sound that is exactly like, for example, an [n] except without vocal fold vibration. It is simply that English has chosen not to use such sounds in its set of distinctive sounds. (It is possible even in English for one of these sounds to become voiceless under the influence of its neighbours, but this will never change the meaning of the word.)
Manners of articulation
A stop consonant completely cuts off the airflow through the mouth. In the consonants [t], [d], and [n], the tongue tip touches the alveolar ridge and cuts off the airflow at that point. In [t] and [d], this means that there is no airflow at all for the duration of the stop. In [n], there is no airflow through the mouth, but there is still airflow through the nose. We distinguish between
nasal stops, like [n], which involve airflow through the nose, and
oral stops, like [t] and [d], which do not.
Nasal stops are often simply called nasals. Oral stops are often called plosives. Oral stops can be either voiced or voiceless. Nasal stops are almost always voiced. (It is physically possible to produce a voiceless nasal stop, but English, like most languages, does not use such sounds.)
In the stop [t], the tongue tip touches the alveolar ridge and cuts off the airflow. In [s], the tongue tip approaches the alveolar ridge but doesn’t quite touch it. There is still enough of an opening for airflow to continue, but the opening is narrow enough that it causes the escaping air to become turbulent (hence the hissing sound of the [s]). In a fricative consonant, the articulators involved in the constriction approach get close enough to each other to create a turbluent airstream. The fricatives of English are [f], [v], [θ], [ð], [s], [z], [ʃ], and [ʒ].
In an approximant, the articulators involved in the constriction are further apart still than they are for a fricative. The articulators are still closer to each other than when the vocal tract is in its neutral position, but they are not even close enough to cause the air passing between them to become turbulent. The approximants of English are [w], [j], [ɹ], and [l].
An affricate is a single sound composed of a stop portion and a fricative portion. In English [tʃ], the airflow is first interuppted by a stop which is very similar to [t] (though made a bit further back). But instead of finishing the articulation quickly and moving directly into the next sound, the tongue pulls away from the stop slowly, so that there is a period of time immediately after the stop where the constriction is narrow enough to cause a turbulent airstream. In [tʃ], the period of turbulent airstream following the stop portion is the same as the fricative [ʃ]. English [dʒ] is an affricate like [tʃ], but voiced.
Pay attention to what you are doing with your tongue when you say the first consonant of [lif] leaf. Your tongue tip is touching your alveolar ridge (or perhaps your upper teeth), but this doesn’t make [l] a stop. Air is still flowing during an [l] because the side of your tongue has dropped down and left an opening. (Some people drop down the right side of their tongue during an [l]; others drop down the left; a few drop down both sides.) Sounds which involve airflow around the side of the tongue are called laterals. Sounds which are not lateral are called central.
[l] is the only lateral in English. The other sounds of Englihs, like most of the sounds of the world’s languages, are central.
More specifically, [l] is a lateral approximant. The opening left at the side of the tongue is wide enough that the air flowing through does not become turbulent.