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Phonetics (Greek, ‘science of voice’) is the branch of linguistics concerned with the physical properties of the sounds produced in speech. A major concern in phonetics becomes clear if we consider the experience of listening to someone speaking an entirely foreign language. Although we can recognize the stream of sounds as speech, it is extremely difficult to distinguish individual sounds. Even when sophisticated methods of acoustic analysis are employed, it emerges that the boundaries between the contiguous units in speech are not at all easy to define. Even though there are good grounds for arguing that, for instance, the word ‘big’ comprises three separate speech sounds (b, i, g), in purely physical terms there are no decisive, clear-cut borderlines between the end of one speech unit and the start of the next. There is a clear tension between, on the one hand, an inherently unified and indivisible flow of speech sounds and, on the other hand, the recognition that distinct speech sounds are identifiable as psychologically real events which can be extracted from the speech signal.
A fundamental aim in phonetics is to be able to transcribe the physical properties of human speech with objective accuracy. An effective transcription system must be able to represent acoustic properties which vary over time. Somewhat paradoxically, however, practical constraints necessitate the use of independent symbols, each symbol representing a discrete unit of speech. In fact, these symbols are very often regarded as targets (rather than discrete, separable units) towards which the configurations of the vocal apparatus are directed. In this way, a compromise is reached, and the fluid nature of the acoustic properties of speech remains acknowledged. The International Phonetic Association has arrived at a set of symbols which is designed so that it can be used to transcribe utterances from any known natural language. Not surprisingly, the prescribed set of symbols (the International Phonetic Alphabet, IPA) does not satisfy all phoneticians. Specifically, it has been argued that the IPA symbols are excessively biased towards the specific characteristics of European languages.
It has also been suggested that the IPA list is not sufficiently independent of the way speech sounds are used to convey meaning in languages (see phonology). Some phoneticians pursue the ideal of a purely phonetic transcription, in which all the sounds of an utterance are transcribed without reference to the structure of the particular source language. Unfortunately, the perceptually-based judgements of phoneticians do not always correspond to the independently measurable acoustic properties of a speech event. In other words, transcription is essentially a subjective process, despite a generally high level of overall agreement among trained phoneticians.
Beyond the problems of representation, phoneticians are involved with a wide range of questions arising from the physical characteristics of speech sounds. In practical terms, recent years have witnessed a great surge of interest in producing computer systems which can process human speech sounds automatically (see computational linguistics). Theoretically, a central interest has been the discovery and explanation of phonetic universals (see language universals). The aim is to account for acoustic properties which occur consistently in all known languages. An example is that around 20% of all languages have only five vowels. But more interestingly, those five vowels almost always follow the same pattern, being akin to the Spanish vowels: [i, e, a, o, u]. MS
Further reading J.C. Catford, A Practical Introduction to Phonetics; , P. Ladefoged, A Course in Phonetics. |
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