phonetics

the general study of the characteristics of speech sounds .

It concerns about :

Articulatory phonetics:
which is the study of how speech sounds are made

Acoustic phonetics:
which deal with the physical properties of speech as sound weaves in the air

Auditory phonetics:
deals with perception ,via the ear ,of speech sounds

one other area ,called
Forensic phonetics:
has applications in legal cases involving speaker identification and analysis of recorded utterances