6.1 Explain the three main types of airstreams as used in the production of human speech sounds
Analyses of Initiation
6.1 Descriptive elements
These are elements of initiation, phonation, articulation (temporal, prosodic, metrical
6.2. Classification of sounds segments by Initiation
This classification is based on the
– Airstream mechanisms and airflow direction.
– The nature of mechanisms that is responsible for setting the air stream in
6.3 Air stream mechanisms
(Speech sounds) Production of speech sounds involves the utilization of a flow of air that
is commonly referred to as an air stream. The air stream is provided or initiated by the
action of some organs of speech. The air stream is the basis of the whole of the sound of
human speech. The initiator sets in motion air stream and thus the initiator is the most
important part of an air stream mechanism. The air stream could be used as ingressive –
to pull in air or as egressive – to push out air.
Types of airstreams
Three main types of airstreams are used in the production of human speech sounds.
Each has a different initiator.
The initiators consist of the lungs and the respiratory muscles. The respiratory muscles
move the walls of the lungs, which then form the initiator. In using the egressive
pulmonic air stream mechanism expiration must become an active process and it must
utilize muscular control. This airstreams is the basis of almost all human speech sounds.
Only the egressive pulmonic airstream is used in the articulation of human speech
sounds. Some languages in special circumstances use the ingressive pulmonic airstream
but not phonetically. For instance, in English the initial sound in the word ‘yes’ utilizes
the ingressive airstream when one is speaking in an off hand manner.
b) Glottalic air stream mechanism
A closed glottis initiates the glottalic airstream. The glottis is the opening between the
vocal cords. The air utilized in this airstream is in the pharynx and above the larynx. The
larynx has muscles that enable it to be pushed up and down in the throat. When it moves
this way and the glottis is closed the movement pushes air out or in within the passage.
The Glottalic airstream has both ingressive and egressive air flow.
i) The egressive Glottalic airstream mechanism
It is utilized in Caucasian, African, central and North American languages. The sounds
produced have a low volume because the air controlled in the glottalic mechanism is not
sufficiently large for more than a small fraction of speech to be uttered at one movement
of the initiator. The vowels produced with this mechanism are inaudible. The sounds
articulated with the egressive Glottalic airstream mechanism are known as ejectives.
Example: Voiceless bilabial ejective /p’/
ii) The ingressive Glottalic airstream mechanism
c) The velaric air stream mechanism
The velaric airstream mechanism is initiated by the velum. The back part of the tongue is
lifted to make firm contact with the velum. This movement forms what is referred to as a
velic closure. The closure sets in motion only that air that is in the mouth. The airstream
is ingressive for, with the lips closed, it utilizes only the inflowing air.
The air stream is used in the production of sounds found in certain African languages, for
example, Zulu, Hottentots and Bushman. The sound segments are known as clicks
because they are articulated with a sucking movement.
d) The oesophageal airstream
The oesophageal airstream is physiologically considered part of the glottalic airstream
mechanism. However, it is only used by those who have undergone laryngectomy. The
air stream still sets in motion the air in the passage between the pharynx and larynx.
Unlike other airstreams, users of this airstream have to practice using it after undergoing
the operation. It is, therefore, not one of the natural airstream mechanisms.