The field of phonetics is a multilayered subject of linguistics that focuses on speech. In the case of oral languages there are three basic areas of study:
Articulatory phonetics: the study of the production of speech sounds by the articulatory and vocal tract by the speaker.
Acoustic phonetics: the study of the physical transmission of speech sounds from the speaker to the listener.
Auditory phonetics: the study of the reception and perception of speech sounds by the listener.
These areas are inter-connected through the common mechanism of sound, such as wavelength (pitch), amplitude, and harmonics.