The subject of phonetics of the english language

Phonetics as a science is concerned with the human noises by which the thought is actualized or given audible shape: the nature of these noises, their combinations, and their functions in relation to the meaning. The phonetic system of English consists of the following four components: speech sounds, the syllabic structure of words, word stress, and intonation

Phonetics is subdivided into practical and theoretical.
Practical or normative phonetics
studies the substance, the material form of phonetic phenomena in relation to meaning.
Theoretical phonetics is mainly concerned with the functioning of phonetic units in the language.

Phonetics is itself divided into two major components: segmental phonetics, which is concerned with individual sounds and suprasegmental phonetics whose domain is the larger units of connected speech: syllables, words, phrases and texts.

All speech sounds have four aspects (mechanisms): articulatory, acoustic, auditory, functional. We may consider the branches of phonetics according to these aspects. Four branches of the subject are generally recognized:
1) Articulatory phonetics is the study of the way the vocal organs are used to produce speech
sounds.
2) Acoustic phonetics is the study of the physical properties of speech sounds.
3) Auditory phonetics is the study of the way people perceive speech sounds.
4) The fourth branch – 'functional phonetics' – is concerned with the range and function of
sounds in specific languages. It is typically referred to as phonology.

Besides the four branches of phonetics described above, there are other divisions of the science: general phonetics, special phonetics, historical (diachronic) phonetics, comparative phonetics. All the branches of phonetics are closely connected not only with one another but also with other branches of linguistics.