Manner of Articulation

In the last lesson, you were introduced to the places of articulation. These are the points in the vocal tract at which the articulators alter the shape of the vocal tract to produce distinct consonant sounds.
However, consonants are further distinguished on the basis of how the articulators alter the shape of the vocal tract. That is, how is the airflow regulated by the tongue or lips.
In the following sections, you will be introduced to the major manners of articulation for pulmonic consonants.
Plosives
A plosive is formed by the complete obstruction of the vocal tract by the articulators. This obstruction is then released, allowing the air to "explode" out of the mouth.
When the air is blocked by the articulator, it begins to raise in pressure. Then, when the air is released, the high pressure air rushes out into the lower pressure area beyond the blockage. This results in a burst of air, signifiying a plosive. In the following diagram, the dots represent the pressure of the air. The higher pressure area have more dots per area, while the lower pressure areas have fewer dots per area.


Fricatives

A fricative is formed by a constriction in the vocal tract by the articulators, such as the tongue or the lips. However, unlike stops, the occlusion (blockage) in the vocal tract is not complete. Some of the air is allowed to come through a very narrow opening. This air becomes turbulent, because of the friction between the airflow and the narrow passage.
Fricatives happen in two ways. One way is simply for the air to flow through a narrow opening, like in the sound . Another ways is for the air to be sped up through a narrow passage and then forced across another area, like the teeth, which is the way the sound is formed. In the following diagram, the dots represent moving air particles. The air behind the occlusion is relatively slow, but the air that is forced between the tongue and the roof of the mouth is much faster and more turbulent.

Affricates

An affricate combines the manners of articulation for the plosive and the fricative. Like a stop, the articulation of the affricate begins with a complete closure of the vocal tract by an articulator. However, when the closure is released, the release is somewhat gradual, providing a narrow space between the articulator and the mouth for the airflow to move through. This narrow space creates an environment similar to a fricative, in that the airflow moving out becomes turbulent for a brief period until full release of the closure.

Nasals

A nasal is formed by the obstruction of the vocal tract and the lowering of the velum. This lowering of the velum alows the airflow to flow out through the nasal cavity, rather than through the oral cavity.

Approximant
An approximant is formed by the constriction of the vocal tract, but with no obstruction in the vocal tract. Therefore, no turbulent airflow, as in a fricative. Instead, the air is allowed to flow freely through the vocal tract.
Examples of approximants in English are , , , .
The sound is also known as a lateral approximant, since the articulators do touch at a central point, but the air is allowed to flow through one or both sides of the contact point.
Summary
In this lesson, you have been introduced to several manners of articulation. These are listed below:
  • Plosive
    • Formed by a blockage of the vocal tract, followed by an explosive release of air
  • Fricative
    • Formed by slight contact between articulators, allowing turbulent airflow
  • Affricate
    • Formed by a blockage of the vocal tract, like plosive, followed by a gradual release of turbulent air, like a fricative
  • Nasal
    • Formed by the lowering of the velum, allowing air to flow through the nasal cavity

  • Approximant
    • Formed by the constriction of the vocal tract, but with no blockage of the airflow
  • Tap
    • Formed by a quick contact between articulators
  • Trill
    • Formed by the rapid vibration of the tongue tip by a current of air
Vowel Classification
In the last two lessons, you were introduced to the classification of consonant sounds. The classification of consonants were shown to be based on three aspects of articulation: place of articulation, manner of articulation, and voicing.
In this lesson, you will be introduced to the classification of vowel sounds. The classifcation of vowels is based on four major aspects: tongue height, tongue backness, lip rounding, and the tenseness of the articulators.
In the first section, you will be introduced to the classification of vowels based on tongue height.
Tongue Height
The first aspect of vowel classification that you will be introduced to is that of tongue height. Vowels are classified in terms of how much space there is between the tongue and the roof of the mouth, which is determined by the height of the tongue.
There are three primary height distinctions among vowels: high, low, and mid.
In English, examples of high vowels are , , , . These are vowels with a relatively narrow space between the tongue and the roof of the mouth. Examples of low vowels are , . These are vowels with a relatively wide space between the tongue and the roof of the mouth. Examples of mid vowels are [e], , , . These are vowels whose tongue positions are roughly between the high and low vowels.
                           These classifications are quite relative, as different languages have different canonical tongue heights for different classifications.As illustration of tongue height, observe the following diagrams for the vowels , , .
As you can see from the diagrams, the tongue height of the high vowel is much higher than that for the low vowel , while the tongue height for the mid vowel lies somewhere in between the two
Tongue Backness
The second aspect of vowel classification that you will be introduced to is that of tongue backness. Vowels are classified in terms of how far the raised body of the tongue is from the back of the mouth, which is called the backness of the tongue.
There are three primary height distinctions among vowels: front, back, and central.
In English, examples of front vowels are , , [e], , . These vowels are articulated relatively forward in the mouth. Examples of back vowels are , , , . These vowels are articulated relatively far back in the mouth.. Examples of central vowels are , . These are vowels whose tongue positions are roughly between the front and back vowels.


These classifications, like the tongue heights, are quite relative, as different languages have different canonical tongue backnesses for different classifications.
As illustration of tongue backness, observe the following diagrams for the vowels , .
As you can see from the diagrams, the articulation of the front vowel is much farther forward than that for the back vowel .

Lip Rounding

Another aspect of vowel classification is the presence or absence of lip rounding. Some vowels, such as the vowels and , are formed with a high degree of lip rounding. Such vowels are called rounded vowels. Some vowels, such as and , are formed without such rounding, and are called unrounded vowels.
Tense vs. Lax
Another aspect of vowel classification is commonly characterized in terms of the tenseness or laxness of the articulators. Some vowels, such as the vowels and [e], are formed with a high degree of tenseness. Such vowels are called tense vowels. Some vowels, such as and , are formed without a high degree of tenseness, and are called lax vowels.
Some languages have a similar distinction in the articulation of vowels. This classification is in terms of the position of the tongue root. In these languages, the primary classificational feature for the vowels and [e] is not that the articulators are tense, but that the root of the tongue is pushed forward, opening up the pharynx. Such a condition is known as Advanced Tongue Root (ATR). Vowels such as and , on the other hand, do not have ATR in those languages that have that distinction.
Summary
In this set of lessons, you have been introduced to the classification of vowel sounds in human language. The four classifications are as follows:
  • Tongue Height
  • Tongue Backness
  • Lip Rounding
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