Introduction
Humans generate phones by using various parts of the respiratory and digestive systems to manipulate airflow.
The Vocal Tract
Definition: The Vocal Tract
The vocal tract is the system of organs used to produce speech.
Familiarizing yourself with the anatomy of the vocal tract is crucial to understanding how sounds are made.
At a fundamental level, the vocal tract comprises the lungs, trachea, larynx, pharynx, epiglottis, oral cavity (including the tongue inside it) and the nasal cavity.
Trachea
The trachea (windpipe) is the pipe that goes down the throat and into the lungs. It is responsible for carrying air into and out of the lungs.
Larynx
The larynx (voice box) is where the vocal folds (vocal cords) reside. The space between the vocal folds is known as the glottis. The larynx’s primary use is in phonation.
Epiglottis
Above the larynx lies the epiglottis, which is a flap of elastic cartilage whose main purpose is to close the entrance to the trachea when swallowing to prevent food from entering the lungs. However, it can also be used to produce certain sounds.
Oral Cavity
The oral cavity is the empty space between the lips and the back of the throat. It is where the teeth and the tongue reside. The tongue is one of the most important organs for speech as it is used in the production of the vast majority of phones.
Nasal Cavity
Above the oral cavity lies the nasal cavity, i.e. the empty space behind the nostrils, extending to the back of the throat.
Pharynx
The pharynx is the empty space behind the nasal and oral cavities, the epiglottis, and above the larynx. It is generally divided into three parts: the nasopharynx (the empty space behind the nasal cavity), the oropharynx (the empty space behind the oral cavity), and the laryngopharynx (the space behind the epiglottis).
Airstream Mechanisms
As previously stated, phones are produced by manipulating airflow within the vocal tract. However, different ways of generating this airflow result in different sounds.
Definition: Initiator
The initiator is the organ in the vocal tract that creates the movement of air necessary for the production of a given phone.
The three main initiators are the lungs, the vocal folds and the tongue and three mechanisms are distinguished based on these initiators.
Pulmonic Mechanism
Definition: Pulmonic Mechanism
The pulmonic mechanism uses the lungs as the initiator of airflow.
The diaphragm is the primary muscle involved in generating airflow by the pulmonic mechanism. It resides below the lungs. When the diaphragm contracts, it flattens and moves downwards, increasing the volume of the lungs and drawing air into them. When the diaphragm relaxes, it moves upwards, compressing the lungs and pushing air out of them.
Definition: Egressive Pulmonic Mechanism
The egressive pulmonic mechanism is the pulmonic mechanism in which the diaphragm relaxes and pushes air out of the lungs.
The vast majority of phones in human languages are pulmonic egressives. In fact, most languages (including all European languages) use only pulmonic egressive sounds.
Definition: Ingressive Pulmonic Mechanism
The ingressive pulmonic mechanism is the pulmonic mechanism in which the diaphragm contracts in order to allow air to flow into the lungs.
The use of pulmonic ingressive phones is extremely limited. In fact, pulmonic ingressive sounds used in actual words have only been found in Damin, a ritual language formerly spoken by speakers of Lardil in Australia. However, pulmonic ingressives are quite common in interjections to indicate various social cues, such as that someone is about to begin speaking.
Notation: IPA for Pulmonic Ingressive
In IPA, pulmonic ingressives are marked by a downwards pointing arrow such as [h↓].
Glottalic Mechanism
Definition: Glottalic Mechanism
This mechanism utilizes two closures of the vocal tract. First, the vocal folds come together and close the glottis entirely. This prevents airflow from going into and out of the lungs. Then, a second closure is produced somewhere else in the vocal tract, usually using the tongue. The airflow is then generated by either raising or lowering the larynx and releasing the second closure, while keeping the glottis sealed.
Definition: Egressive Glottalic Mechanism
The egressive glottalic mechanism is the glottalic mechanism in which the larynx is raised.
When the larynx is raised, it compresses the air between the two closures. The built-up pressure subsequently causes the air to flow outwards when the second closure is released.
Definition: Ingressive Glottalic Mechanism
The ingressive glottalic mechanism is the glottalic mechanism in which the larynx is lowered.
When the larynx is lowered, the increase in the space between the two closures causes a drop in the pressure of the air between them. When the second closure is released, this difference in pressure causes air to be sucked in.
Velaric Mechanism
Definition: Velaric Mechanism
The velaric mechanism uses the tongue as the initiator of airflow.
First, the back of the tongue moves upwards and backwards to close the throat. Then, the front of the tongue is raised to create another closure somewhere in the oral cavity. Finally, the part of the tongue between the two closures is lowered, causing the air pressure between them to drop. When the tip of the tongue releases the closure, air is sucked in.
Phonation
Definition: Phonation
Here, the primary distinction is between voiceless and voiced sounds.
Definition: Voiceless Sound
A phone is voiceless if the vocal folds do not vibrate when the sound is produced.
English has many voiceless sounds such as the “s” in “sing” or the “th” in “thin”.
Definition: Voiced Sound
A phone is voiced if the vocal folds vibrate when the sound is produced.
Examples of voiced sounds in English include the “z” in “zone” and the “b” in “boot”.
Tip: Testing for Phonation
You can easily determine whether a phone is voiced or voiceless by placing your hand on your throat, below your chin (near your Adam’s apple, if you have one) and then making the sound. If you feel vibration when the sound is produced, then it is voiced. Otherwise, it is voiceless.
Voices
There are multiple ways in which a phone can be voiced depending on the precise way in which the vocal folds vibrate during its production.
| Voice | Description | Example |
|---|---|---|
| Modal Voice | This is the normal voice you usually use when speaking. | |
| Breathy Voice | This voice is produced when the vocal folds vibrate without appreciable contact between each other. | |
| Creaky Voice (Vocal Fry) | This voice is produced when the vocal folds vibrate in an irregular manner with low frequency. |
Notation: IPA for Voices
The IPA notation for the various voices is as follows:
- By default, every voiced phone is assumed to be pronounced with modal voice and this does not require any explicit notation.
- Breathy voice is indicated either with the diacritic
◌̤or the superscript ◌ʱ - [d̤], [a̤], [dʱ], [aʱ].- Creaky voice is indicated by the
◌̰diacritic - [a̰], [d̰].
In most languages, the type of voice is not contrastive - it does not affect the meaning of the words spoken. However, there are languages such as the Jalapa dialect of Mazatec where pronouncing the same phone with different voices can result in drastically different meanings. Nevertheless, these are very rare.
Articulation
Definition: Articulation
Articulation refers to the mechanism by which airflow is modified in order to produce a given phone.
There are three main aspects of articulation - the articulators, the place or point of articulation and the manner of articulation.
Definition: Articulator
The articulators are the organs used to modify airflow.
The most common articulator is the tongue.
Definition: Place of Articulation
The place of articulation (point of articulation) is the location where the modification of airflow happens.
Definition: Manner of Articulation
The manner of articulation is the precise way in which airflow is modified.