Phonetics deals with the production of speech sounds by humans, often without prior knowledge of the language being spoken. Phonology is about patterns of sounds, especially different patterns of sounds in different languages, or within each language, different patterns of sounds in different positions in words etc
In contrast to phonetics, phonology is the study of how sounds and gestures pattern in and across languages, relating such concerns with other levels and aspects of language. Phonetics deals with the articulatory and acoustic properties of speech sounds, how they are produced, and how they are perceived. As part of this, phoneticians may concern themselves with the physical properties of meaningful sound contrasts or the social meaning encoded in the speech signal (e.g. gender,sexuality, ethnicity, etc.). However, a substantial portion of research in phonetics is not concerned with the meaningful elements in the speech signal.While it is widely agreed that phonology is grounded in phonetics, phonology is a distinct branch of linguistics, concerned with sounds and gestures as abstract units (e.g., features, phonemes, mora, syllables, etc.) and their conditioned variation (via, e.g., allophonic rules, constraints, or derivational rules).Phonology relates to phonetics via the set of distinctive features, which map the abstract representations of speech units to articulatory gestures, acoustic signals, and/or perceptual representations.
2. The Relationship between Phonetics and Phonology
Most phonetic work falls into the sub-field of articulatory phonetics (the study of the human vocal tract, the International Phonetic Alphabet, and how to make and describe language sounds), but with recent advances in computers and the availability of good phonetics software, there has been a recent boom in acoustic research (the physical properties of sounds-wave forms, pitch, intensity, spectrograms).
Phonology cares about the entire sound system for a given language. The goal is to formulate a model/theory which explains not only the sound patterns found in a particular language, but the patterns found in all languages.
Examples of questions which are interesting to phonologists are: How do sounds change due to the sounds around them? (For example, why does the plural of cat end with an 's'-sound, the plural of dog end with a 'z'-sound, and the plural of dish end in something sounding like 'iz'?) How do sounds combine in a particular language? (For example, English allows 't' and 'b' to be followed by 'l' - rattle, rabble, atlas, ablative - so why then does 'blick' sound like a possible word in English when 'tlick' does not?)
The classic generative model of linguistics provides a straightforward view of the relationship between phonetics and phonology. According to
Chomsky and Halle, phonological representations, seen as classificatory feature bundles, are converted by phonological rules into a phonetic representation in which features take on scalar values. Phonetic and sociolinguistic studies, however, have shown for some time that this view is simplistic: (a) repetitions of the same utterance by the same speaker can differ substantially from one another; (b) speakers of the same linguistic variety show systematic differences in the realization of
the same category; (c) different realizations of the “same” category (say, segments transcribed as [s]) are also found cross-linguistically.
In phonetics, intra- and inter-speaker variation within the same linguistic variety has been typically viewed as noise to be stripped from the signal. On the other hand, cross-linguistic differences have often been said to have a functional basis. For example, Cohn showed that vowel nasalization is much more extensive in English, in which it is not distinctive, than in French, which contrasts oral and nasal vowels.