Consonant parameters (continued)

Manners of articulation

Manner of artiulation is the type of closure made by the articulators and the degree of the obstruction of the airstream by those articulators.

Constriction degree

Place of articulation refers to where the narrowing occurs -- which active articulator gets close to which passive articulator. Constriction degree refers to how close they get. The main constriction degrees are:

• stop: the active articulator touches the passive articulator and completely cuts off the airflow through the mouth. English stops include: [p]、[d]、[k]、[m].
• fricative: the active articulator doesn't touch the passive articulator、but gets close enough that the airflow through the opening becomes turbulent. English fricatives include [f]、[]、[z].
• approximant: the active articulator approaches the passive articulator、but doesn't even get close enough for the airflow to become turbulent. English approximants include [j]、[w]、[]、and [l].
• affricate: Affricates can be seen as a sequence of a stop and a fricative which have the same or similar places of articulation. They are transcribed using the symbols for the stop and the fricative. If one wants to emphasize the affricate as a "single" sound、a tie symbol can be used to join the stop and the fricative (sometimes the fricative is written as a superscript).

Notes:

• A stop cuts off airflow through the mouth . Airflow through the nose does not matter -- you can have both oral and nasal stops. Oral stops are often called plosives、including in the IPA chart. Nasal stops are usually just call ed nasals.
• Approximants that are apical or laminal are often called liquids (e.g.、[]、[l]). Approximants that correspond to vowels are often called glides (e.g.、[j] corresponds to [i]、[w] to [u]).
• English has the affricates [t] and [d]. The stop and the fricative halves of these affricates are at the same place of articulation: the stop is in fact postalveolar rather than alveolar. We could be explicit about this and underline the [t] and [d] (in IPA、a minus sign under a symbol is a diacritic meaning "pronounced further back in the mouth")、but most phoneticians believe this difference in the place of articulation is so predictable that it doesn't have to be marked.

State of the glottis

For now、we can simply use the terms "voiced" and "voiceless" to answer the question of what the vocal cords are doing:

• In voiced sounds、the vocal cords are vibrating.
• In voiceless sounds、the vocal cords are not vibrating.

Ultimately、we will see there are different ways of being voiced or voiceless. The vocal cords can do a number of things. They can:

• be held so wide apart that the air makes no sound passing through them. (This is nice when you have to breathe 24 hours a day、but not as useful for speaking.)
• be held closer together、so that the air passing through them becomes turbulent. This quality of sound is called breathiness. It is what is happening in apsiration and in the sound [h].
• be held together so that the air passing through them causes them to vibrate. This is called voicing.
• be held together so tightly that no air can pass through at all、as in a glottal stop.

(By varying their tension and position、the vocal cords can also produce many other effects like breathy voicing、creaky voicing、and falsetto.)

What the vocal cords are doing is independent of what the higher parts of the vocal tract are doing. For any place of articulation and any degree of stricture、you can get two different sounds: voiced and voiceless. For example、[t] and [d] are formed identically in the mouth; the difference is that the vocal cords vibrate during a [d] but not during a [t]. (The obvious exception is the glottal place of articulation -- you can't vibrate your vocal cords while making a glottal stop.)

In each cell of the IPA chart、the symbol for the voiceless sound is shown to the left and that for the voiced sound to the right. Some rows only have voiced symbols (e.g.、nasals and approximants). You can write the corresponding voiceless sound using the voiceless diacritic (a circle under the voiced symbol).

　

Nasality

The soft palate can be lowered、allowing air to flow out through the nose、or it can be raised to block nasal airflow. As was the case with the vocal cords、what the soft palate is doing is independent the other articulators. For almost any place of articulation、there are pairs of stops that differ only in whether the soft palate is raised、as in the oral stop [d]、or lowered、as in the nasal stop [n].

　

Laterality

When you form an [l]、your tongue tip touches your alveolar ridge (or maybe your upper teeth) but it doesn't create a stop because one or both sides of the tongue are lowered so that air can flow out along the side. Sounds like this with airflow along the sides of the tongue are called lateral、all others are called central (though we usually just assume that a sound is central unless we explicitly say it's lateral).

The side of the tongue can lower to different degrees. It can lower so little that the air passing through becomes turbulent (giving a lateral fricative like [] or []) or it can lower enough for there to be no turbulence (a lateral approximant). The [l] of English is a lateral approximant.

Airstream mechanism

Speech sounds need air to move. Most sounds (including all the sounds of English) are created by modifying a stream of air that is pushed outward from the lungs. But it's possible for the air to be set in motion in other ways. Sounds which use one of the other three most common airstream mechanisms are called ejectives、implosives、and clicks. We'll discuss these possibilities later in the course.

Describing consonant segments

A consonant sound can be described completely by specifying each of the parameters for place and manner of articulation. For example、[k] has the following properties:

　

active articulator	tongue body (dorsum)
passive articulator	soft palate (velum)
constriction degree	stop
state of glottis	voiceless
nasal	no
lateral	no
airstream mechanism	normal

So [k] is a voiceless oral central dorso-velar stop.

http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/notes.htm

What is Coarticulation?

An articulation which takes place involving in a simultaneous or overlapping way more than one point in the vocal tract. When two adjacent sounds are coarticulated、one sound segment tends to be assimilated by another sound.  Consonants vary their place of articulation so that they become more like the neighboring sound. Coarticulation may be generally defined as "the overlapping of adjacent articulations" (Ladefoged 1993: 55) or as two articulators "moving at the same time for different phonemes" (Borden and Harris 1984:130).

The classification of coarticulation:

Based on the direction of the modification effect、there are two types of coarticulation: anticipatory coarticulation and perseverative coarticulation.

1. anticipatory coarticulation: an articulator not involved in a particular sound begins to move in the direction of an articulation neededfor a later sound; a sound is affected by its following sound.

for example、the rounding of the lips during [s] in "swim" is due to the anticipation of the lip action required for [w].  

2. perseverative coarticulation: the persistence of an aspect of the articulation of one sound into the following sound; that is 、a sound is affected by its preceding sound.

for example、the nasalization of a vowel after a  nasal consonant.

e.g. when 「it is』 [It Iz] is elided into [Its],the voicelessness associated with the [t] persists into the next sound. This is known as preservative coarticulation.

e.g. the word "dogs" is pronounced  [dOgz] where  the ending  [s] is assimilated to [z] by the influence of the preceding voiced [g].

in general、English may be said to be an anticipatory language—that is、one in which the articulations of the sounds yet to come are anticipated to some extent. some other languages、such as french or italian、are more preservative in that the articulation of one sound tends to persevere、or continue、into the following sound.

further reading:

 Ladeforged、Peter. 2001.A Course in Phonetics . 4th.ed. Harcourt College Publishers.