Definition - The study of phones (i.e. speech sounds). As opposed to phonology, which is the study of phonemes (meaningful speech sounds).

1. It consists of three branches: acoustic phonetics, auditory phonetics, and articulatory phonetics.

Etymology -
The word derives from the Greek phonetikos, vocal (from phone, sound or voice).

Oxford English Dictionary -
Its first citation in the sense "scientific study of speech" is from 1841:
"Phonetics … determines (amongst other things) the systematic relation of Articulate Sounds …."
(Latham Eng. Lang. ii. ii. 113 )

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