Linguistic information transmitted by the sender encodes shaped movements of articulators. The movement of the articulators produces a disturbance of air molecules. Movement of molecules is transmitted in the form of sound wave. Auditory system of the receiver picks up the sound wave and the system perceiving her processes by extracting linguistic information. Linguistic information is encoded in the sound wave.
Acoustic classification of speech sounds
Acoustic classification of speech sounds can be summarized as follows:
IMPORTANT TERMS:
Sound wave
The result of the passage of air through the glottis is the issuance of a series of successive puffs of air at the rate of opening and closure of the vocal cords
For the production of the sound wave of air molecules must enter vibration, which is achieved by passing through the creases vowels.
"Sound wave: spread of a disturbance on a material medium such as air, in the form of a series of compressions and alternate rarefactions affecting each particle components of this medium."
The cycle of a vibrating movement
- Force to move the molecule
- Departure from the initial position of rest
- Back to start due to elasticity
- Shift towards the opposite side by inertia
- Back to initial position
Amplitude of the vibratory movement
Distance between resting position and the point of maximum displacement.
It depends on the force applied initially and resistance to provide the environment that produces vibration.
The amplitude is quantified pressure from physical view units or units of decibels (dB) intensity perceptive perspective.
"Amplitude: is the distance from the point of rest to the point of maximum displacement of a particle in vibration." "Is, therefore, increase or decrease the maximum air pressure during a certain sound vibrating cycle."
Length of the vibrating movement
It depends on the force applied initially and resistance to provide the environment that produces vibration.
The duration of the sounds of speech is quantified in thousandths of a second, or milliseconds (ms).
Frequency of the vibration movement
Swing movement is repeated several times in the time, giving rise to a periodic sound characterized by repetition in a series of cycles
Vibrating motion of a molecule of air
Number of times it goes idle position (A) to the point of maximum separation this position (B), is again resting point (C), it comes back to the point of maximum separation (D) and returns to the idle position (E), i.e. number of cycles per unit time.
The unit of frequency is Hertz (Hz), equivalent to one cycle per second "Cycle: full vibration of a particle, composed of stages of compression and rarefaction." "Thus, a cycle is the portion of the sound wave extending from any point to the next point where air pressure begins to suffer identical changes."
"Frequency: number of cycles performed in the unit of time, conventionally the second."
"Periodic wave: wave which repeats the profile of a cycle at regular intervals of time."
The sound wave is the result of the vibration of air molecules, and can be defined on the basis of:
- its breadth
- its frequency
- the time during which the movement takes place.
"Complex wave: wave resulting from the addition of a number of simple waves."
"Resonance: phenomenon by which a body called the resonator and it has a natural tendency to vibrate at certain frequency will experience greater amplitude vibrations when post is another vibrant body at a similar frequency movement."
Characteristics of the source
Sounds with a periodic source:
- Produced with the vocal cords vibration
- Sound sounds – produced with a periodic source
- Unvoiced sounds – produced without the intervention of a periodic source
Acoustic classification of speech depending on the source and filter sounds
Source | Filter | Kind of sounds |
Periodic | Fixed, oral | oral vowels |
Periodic | Fixed, oral + nose | nasal vowels |
Periodic | Variable, oral | diphthongs |
Aperiodic continuous | Fixed, oral | voiceless fricatives |
Aperiodic impulse | Variable, oral | plosives oral deaf |
Aperiodic continuous + regular | Fixed, oral | fricatives sound |
Aperiodic impulse + regular | Variable, oral | plosives sound oral |
Aperiodic impulse + regular | Variable, oral + nose | plosives sound nasal |
Aperiodic continuous + regular | Variable, oral | semi-vowels lateral and vibrant |
Extracted from: Gil Fernandez, j. (1988). The sounds of language.