Overview of Phonetics and Phonology

Phonetics is one of the branches of linguistics. Linguistics is an academic field of inquiry that embraces the study of language as a whole, whereas phonetics narrowly focuses on examining, describing and understanding the sounds of human speech. 

As a discipline, phonetics is further broken down into three different fields — articulatory, acoustic and auditory phonetics — with each one contributing its own perspective to the study of human speech sounds. Taken together, these three fields focus on how sounds are produced by the human speech organs, what their actual physical properties are and, finally, how the hearer of the sounds perceives them.

Articulatory phonetics is the oldest of the three fields and is the one in which the concepts that are fundamental to phonetic study were first defined. This field focuses on the speaker and studies how air and the different parts of the vocal tract move and interact to produce the actual sounds of speech. For example, research might be done on how the lips, teeth and air are used to produce the sound at the beginning of the word "far." In addition, this field devotes study to the classification and categorization of speech sounds, such as vowels and consonants, to be able to assess and provide therapy for different speech disorders by teaching pronunciation and how to correctly form sounds and words.

Phonology is a branch of linguistics concerned with the systematic organization of sounds in languages. 

It has traditionally focused largely on study of the systems of phonemes in particular languages (and therefore used to be also called phonemics, orphonematics), but it may also cover any linguistic analys is either at a level beneath the word (including syllable, onset and rhyme, articulatory gestures, articulatory features, mora, etc.) or at all levels of language where sound is considered to be structured for conveying linguistic meaning. Phonology also includes the study of equivalent organizational systems in sign languages.

The word phonology (as in the phonology of English) can also refer to the phonological system (sound system) of a given language. This is one of the fundamental systems which a language is considered to comprise, like its syntax and its vocabulary.

Phonology is often distinguished from phonetics. While phonetics concerns the physical production, acoustic transmission and perception of the sounds of speech, phonology describes the way sounds function within a given language or across languages to encode meaning. For many linguists, phonetics belongs to descriptive linguistics, and phonology to theoretical linguistics, although establishing the phonological system of a language is necessarily an application of theoretical principles to analysis of phonetic evidence. Note that this distinction was not always made, particularly before the development of the modern concept of phoneme in the mid-20th century. Some subfields of modern phonology have a crossover with phonetics in descriptive disciplines such as psycholinguistics and speech perception, resulting in specific areas like articulatory phonology or laboratory phonology.

Reference: Wikipedia & © Andrew Moore, 2002