Phonetics is the scientific study of speech sounds. Unlike phonemics (the study of the organization of speech sounds into a linguistic system), phonetic studies can be carried out without necessary regard for the language system within which they may be found. That is, researchers making a phonetic inventory of the sounds of a language, say English, will note that speakers of English produce sounds such as [t] and [th]; they may not be concerned with whether these sounds are contrastive in English (they are not).
Traditionally, researchers have used three approaches defined by the types of problem under investigation. Auditory phonetics is the study of the perception and processing of speech sounds. This branch of phonetics often makes use of highly specialized equipment that tests people’s ability to hear or to distinguish between particular speech sounds. Acoustic phonetics is the branch of phonetics that deals with the physical properties of sound waves moving through the air, as recorded by instruments such as a sound spectrometer. Articulatory phonetics is the study of the gestures, made in the vocal tract, that result in the production of speech sounds. Traditionally, anthropologists have been most interested in this branch because it enables them to inventory the sounds of a previously unwritten language, in preparation for making a phonemic study of the language, and also to facilitate the recording of linguistic data.
Speech sounds are produced by moving air through the vocal tract, which extends from the larynx to the lips and includes the nasal cavity. Speech sounds are divided into two natural classes: vowels and consonants. Vowels are produced by passing air through the tract without obstruction; vowel quality depends on the positioning and tension of the tongue muscle, and by presence or absence of lip rounding. For example, [u] (the vowel in boot) is high, back, tense, and rounded; [a] (cot) is low, back, lax, and unrounded.
Consonants are produced by obstructing the air in some way as it passes out of the throat. Consonants are usually described in terms of the state of the larynx (voiced or voiceless); the place of articulation (bilabial, labiodental, etc.); and the manner of articulation (stop, fricative, nasal, etc.). For example [b] is a voiced bilabial stop; [f] is a voiceless bilabial fricative.
Lieberman and Crelin attempted to determine the speech sounds that Neandertal hominids were capable of making by making a computer-generated model of their vocal tract, and then using this to determine the sounds they could have produced. Although they probably underestimated the Neandertals’ speech ability, this was an innovative and important use of acoustic phonetics.
The term phonetic is sometimes used by English speakers, especially those in the educational community, to refer to spelling which is based on sound rather than on traditional orthography. This usage is erroneous; the proper term is phonemic or phonological spelling (see phonology).
Phonetics has probably gained its widest currency in contemporary anthropology as the source for the term etics.
References:
- Ladefoged, P. (1975). A course in phonetics. New York: Harcourt Brace Jovanovich.
- Lieberman, P. (1984). The biology and evolution of language. Cambridge, MA: Harvard University Press.
- Pike, K. (1976). Phonemics: A technique for reducing languages to writing. Ann Arbor: University of Michigan Press.
- Smalley, W. A. (1973). Manual of articulatory phonetics. South Pasadena, CA: William Carey Library.
