The production of speech goes through three stages: pronunciation-transmission-perception.
All sounds originate from the vibration of the sounding body.When the pronunciation body vibrates, it disturbs the surrounding air or other media, causing it to fluctuate, thus forming sound waves.
For speech sound, sound can be produced in two ways: the vortex generated by the vibration of the vocal cords or the narrow part of the vocal tract. After the sound passes through the resonance system formed by the airflow channel or passes through the filter, the frequency spectrum changes. After passing through the lips and nasal cavity The time spectrum has changed again.The difference between different phonemes can be caused by the sound source, or by the shape of the vocal tract and the length of the air column.
After the sound wave occurs, it passes through a resonance system, and its frequency spectrum can be vocally changed.Such a resonance system is equivalent to an acoustic filter, and the function of the filter can be expressed by the frequency response curve, that is, the gain or output of each frequency.Filtering plays an important role in the production of speech.The throat, mouth, teeth, lips, and nasal cavity form a vocal tract. This vocal tract is a resonance cavity that filters the sound waves emitted from the trachea or vocal cords.After that, through the conduction of the outside air, it reaches the human ear and produces the sensation of voice.