Describing consonants

What makes one consonant different from another?

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
voicing

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.)

Voicing

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 souns have identical places and manners of articulation, but one has vocal fold vibration and the other doesn't. The of thigh and the of thy are one such pair. The others are:

voiceless voiced

The other sounds of English do not come in voiced/voiceless pairs. is voicess, and has no voiced counterpart. The other English consonants are all voiced: , , , , , , and . 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

Stops

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.)

Fricatives

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

, and

Approximants

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

, and

Affricates

An affricate is a single sound composed of a stop portion and a fricative portion. In English

, 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

, the period of turbulent airstream following the stop portion is the same as the fricative

. English

is an affricate like

, but voiced.

Laterals

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 doen'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.

Places of articulation

The place of articulation (or POA) of a consonant specifies where in the vocal tract the narrowing occurs. From front to back, the POAs that English uses are:

Bilabial

In a bilabial consonant, the lower and upper lips approach or touch each other. English [p], [b], and [m] are bilabial stops.

The sound [w] involves two constrictions of the vocal tract made simultaneously. One of them is lip rounding, or a bilabial approximant.

Labiodental

In a labiodental consonant, the lower lip approaches or touches the upper teeth. English [f] and [v] are bilabial fricatives.

Dental

In a dental consonant, the tip or blade of the tongue approaches or touches the upper teeth. English

and

are dental fricatives. There are actually a couple of different ways of forming these sounds:

The tongue tip can approach the back of the upper teeth, but not press against them so hard that the airflow is completely blocked.
The blade of the tongue can touch the bottom of the upper teeth, with the tongue tip protruding between the teeth -- still leaving enough space for a turbulent airstream to escape. This kind of and is often called interdental.

Alveolar

In an alveolar consonant, the tongue tip (or less often the tongue blade) approaches or touches the alveolar ridge, the ridge immediately behind the upper teeth. The English stops [t], [d], and [n] are formed by completely blocking the airflow at this place of articulation. The fricatives [s] and [z] are also at this place of articulation, as is the lateral approximant [l].

Postalveolar

In a postalveolar consonant, the constriction is made immediately behind the alveolar ridge. The constriction can be made with either the tip or the blade of the tongue. The English fricatives

and

are made at this POA, as are the corresponding affricates

and

Retroflex

In a retroflex consonant, the tongue tip is curled backward in the mouth. English

is a retroflex approximant -- the tongue tip is curled up toward the postalveolar region (the area immediately behind the alveolar ridge).

Palatal

In a palatal consonant, the body of the tongue approaches or touches the hard palate. English [j] is a palatal approximant -- the tongue body approaches the hard palate, but closely enough to create turbulence in the airstream.

Velar

In a velar consonant, the body of the tongue approaches or touches the soft palate, or velum. English [k],

, and

are stops made at this POA. The [x] sound made at the end of the German name Back or the Scottish word loch is the voiceless fricative made at the velar POA.

As we have seen, one of the two constrictions that form a [w] is a bilabial approximant. The other is a velar approximant: the tongue body approaches the soft palate, but does not get even as close as it does in an [x].

Glottal

The glottis is the opening between the vocal folds. In an [h], this opening is narrow enough to create some turbulence in the airstream flowing past the vocal folds. For this reason, [h] is often classified as a glottal fricative.

Summary of English consonants

voiceless	bilabial	plosive
voiced	bilabial	plosive
voiceless	alveolar	plosive
voiced	alveolar	plosive
voiceless	velar	plosive
voiced	velar	plosive
voiceless	postalveolar	affricate
voiced	postalveolar	affricate
voiced	bilabial	nasal
voiced	alveolar	nasal
voiced	velar	nasal
voiceless	labiodental	fricative
voiced	labiodental	fricative
voiceless	dental	fricative
voiced	dental	fricative
voiceless	alveolar	fricative
voiced	alveolar	fricative
voiceless	postalveolar	fricative
voiced	postalveolar	fricative
voiced	retroflex	approximant
voiced	palatal	approximant
voiced	labial + velar	approximant
voiced	alveolar	lateral approximant
voiceless	glottal	fricative

Consonant charts

It is often useful to display the consonants of a language in the form of a chart. There is a conventional way of doing so:

Columns show places of articulation, arranged (roughly) from the front of the vocal tract to the back.
Rows show manners of articulation.
Within each cell, the symbol for a voiceless sound is shown toward the left of the cell and the symbol for a voiced sound toward the right.

The following is the chart for English consonants:

bilabial labiodental dental alveolar postalveolar retroflex palatal velar glottal

plosive p b t d k

nasal m n

fricative f v s z h

approximant (w) j (w)

lateral approximant l

affricate

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