It is important to understand the mechanisms of speech production because almost always speech is affected by hearing loss. Here is a basic overview of what takes place inside our bodies during the act of speech production.
The steady stream of air as we exhale is the energy source for speech production. Sounds which come from our mouth, or even our nose, are the result of interruptions of a stream of air moving from the lungs through:
--trachea
--larynx
--pharynx
--oral cavity
--nasal cavity
The speech process itself consists of 3 structures:
1.) Structure of respiration
2.) Structure of resonation
3.) Structure of articulation
The first structure, structure of respiration, is the structure which is our power source to speak. The exhaled air is our energy source for speech. The organs involved in respiration are the trachea, rib cage, thorax, abdomen, diaphragm, and lungs.
How it works:
Our lungs first expand which creates negative pressure and makes air available for speaking. Then to actually speak, our lungs deflate and our rib cage contracts forcing the air out, up into our trachea.
The second structure, structure of resonation, is the structure which vibrates/makes sound. The organs invovled in this structure are the larnyx, and the vocal cords/folds. The vocal cords are part of the larynx. The vocal cords are the organ responsible for sound!
How it works:
When we talk, the vocal cords open and close rapidly. Air travels up the larynx, causing pressure to build up which causes the vocal cords to be pushed apart. A reduction of pressure causes the vocal cords to be pulled back together. This vibration (pushing/pulling of the vocal cords) is what is responsible for making sound (pitch and loudness). The larynx also acts as a gate between the lungs and mouth. It opens and closes to control the flow of air from the lungs. The larynx also closes so that food or liquid do not enter the trachea and lungs. Hence the saying, "It went down the wrong pipe."
The third structure, structure of articulation, is responsible for creating different sounds of speech. The joining together of speech organs for production of speech sounds is called articulation. The organs involved in this structure is everything from the lips up to the vocal cords. This includes the lips, teeth, tongue, alveolar ridge, soft/hard pallate, and jaw.
How it works:
By moving and shaping these articulators, it enables us to produce different speech sounds.
In brief, the air flow from the lungs provides energy for speech production, which in turn allows for the vocal cords to convert this energy into an audible noise. The articulators--through altering the shape of the vocal tract--transform the noise into detectable speech sounds.
