Concepts of Phonetics and Phonology.

Phonetics: Is a branch of linguistics that comprises the study of the  sounds  of human speech,  or in the case of sign languages the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs (phones): their physiological production, acoustic properties,  auditory perception, and neurophysiological status.

Phonology: Is the study of the rule system that governs how particular speech sounds are used to produce meaningful words. It investigates the systematic organization of sounds in a particular language. In particular, phonology is concerned with phonemes. These are speech sounds that are capable of creating a distinction in meaning between different words. If two speech sounds can contrast to make a distinction in meaning then they are said to be phonemes. For example, the words tin and din form what is known as a minimal pair

Generative Phonology 

is a branch of generative linguistics that determines the underlying set of rules governing the pronunciation of words in a person's native language. In general, generative linguistics refers to the theory that all human language is generated from linguistic structures that are hard-wired into the brain at birth.

 As a person acquires his or her native language, the structures that apply to that particular language are activated. According to the theory of generative phonology then, the person also acquires certain rules about what sounds can be combined in which ways. Phonology is closely related to phonetics, except that phonetics refers to the sounds that are actually produced within a language, rather than the rules that govern the sounds.

The results of generative phonology can be seen in the way one word is derived from another within a language. In English, for instance, the prefix "in-" is often applied to a root word to negate it. In some instances, however, the combination of this prefix and the initial sounds of the root produce a combination of sounds that violates the rules English phonology, so the prefix or root is modified in some way. The word "material," for example, becomes "immaterial" with the prefix "im-" rather than "in-", because the [inma] pronunciation is not allowable. At some point, speakers of the English language modified this word so that it would fit better with the rules of its phonology.  


 Phonological processes

Children below the age of about 4;06 years may not have sufficient ability to fully co-ordinate the movement of their vocal apparatus. As a consequence, certain sounds, sound combinations or transitions from one sound to another may be currently too difficult. The child may, therefore, simplify the production of complex words. However, in the typically developing child, these simplifications are not random but fairly predictable.

Many so-called phonological simplifying processes have been identified. In fact, there are far too many to cover adequately in this article. However, I will provide some selected examples that will serve to illustrate how phonological processes operate. We will consider two broad categories: (1) structural simplifications, and (2) systemic simplifications.

Discussion
	The following are crucial components of generative phonology:
	Levels of phonological representation Generative phonology posits two levels of phonological representation: An underlying representation is the most basic form of a word before any phonological rules have been applied to it. Underlying representations show what a native speaker knows about the abstract underlying phonology of the language. A phonetic representation is the form of a word that is spoken and heard.

http://www-01.sil./GlossaryOfLinguisticTerms/WhatIsGenerativePhonology.htm

Structural Simplifications

            Structural simplifications involve some alteration to the structure of a particular word. We will consider three:

·         Reduplication

 occurs whenever the initial CV syllable in a multisyllabic word is repeated. Consider the word bottle said as bobo .In this example, the first syllable is reduplicated. This is a fairly simple structural process that can be summarized as:

syllable1 syllable2 → syllable1 syllable1

Other examples include biscuit being said as bibi, and water being said as wawa.

·         Deletion

A simple way to alter the structure of a word is to omit particular speech segments. There are two main speech segments that are typically deleted: (1) consonants, and (2) weak syllables.

·         Consonant deletion

         Consonant deletion occurs whenever a consonant in syllable-initial or syllable-final position is omitted. Children may delete sounds at the beginning of words (initial consonant deletion), e.g. catbecomes at, boat becomes oat or at the ends of words (final consonant deletion), e.g. lidbecomes li, cup becomes cu.

Consonant deletion is a typical phonological process for children between the ages of 2;00-3;06 years.

·         Weak syllable deletion

Weak syllable deletion occurs whenever the unstressed or weak syllable of a multi-syllabic word is omitted. In this process whole syllables are deleted. These are typically unstressed syllables (e.g. the ‘ba’ in banana; the ‘to’ in octopus). So, for example, banana may become nana; octopus may become occur. This is a typical process In children between the ages of 2-4 years.

Metathesis occurs when two consonants within a syllable are placed in a different order.

            In sum, there is a reordering of the sequence of consonants (C) and vowels (V) within a syllable. For example, in a CVC sequence the first and last consonants may be reversed, e.g. cupbecomes puc; dog becomes god.

·         Cluster reduction: occurs when one or more consonants in a cluster is omitted.

            We know that some words in English are structured with clusters of more than one consonant in a sequence, e.g. plan (CCVC), mast (CVCC).

            These clusters may be deleted completely, e.g. plan (CCVC) becomes an (VC); mast (CVCC) becomes ma (CV). Alternatively the cluster may be partially reduced by only articulating one of the consonants in the cluster, e.g. plan (CCVC) may become pan (CVC) or lan (CVC); mast (CVCC) may become mas(CVC) or mat (CVC).Cluster reduction is often observed in children between 2;00-3;06 years of age.

http://www.speech-therapy-information-and-resources.com/phonology.html

Generative phonology and underlying representations

We have considered so far two different levels of abstraction in representing the sound structure of a language: a phonetic level of representation which includes aspects of pronunciation which are at least shared by a community/dialect group, and which above all includes the variability due to context effects; and a phonemic level of representation which is formed from a finite number of phonemic units and which factors out the contextual influences.

It has been a particular hallmark of a branch of phonology known as Generative Phonology, that came to prominence with Chomsky & Halle's (1968) Sound Pattern of English, to consider a more abstract representation which will call an underlying representation that allows phonological rules and principles to be more transparently and economically stated.

Their emphasis in the Sound Pattern of English is to eliminate redundancy from phonological analyses. We already do this to a certain extent, of course, in representing words using the phonemic rather than a phonetic representation: that is, there are some aspects of pronunciation that are redundant (e.g. aspiration of oral stops in English) and so we factor out this redundancy and subsequently fill it in by rule. We therefore of course also necessarily end up with a considerably more abstract sound representation of the word (e.g. /pɪn/ rather than [pʰɪn]) i.e. one which is one stage further removed than a phonetic transcription from the actual details of the production of speech and how the vocal organs are coordinated.

In the Sound Pattern of English, one of the main aims is to factor out many more redundancies from the words' phonological representations and to fill in these redundancies by rule. This in turn results in a representation which is a good deal more abstract than the phonemic forms we have been considering. Furthermore, these highly abstract representations are presumed to form part of the talker's knowledge of the language. -- they might be how the words are encoded in the mental lexicon.

As an example, consider some data reported by Mohanan (1992) and discussed in Kenstowicz (1994). In Singapore English, as in many dialects of English, talkers simplify word-final consonant clusters by deleting the final stop. For example, words like 'task', 'lift', 'list' are produced as /tɑs/,/lɪf/,/lɪs/, i.e. without the final /t/. Now consider the pluralisation rule (in all standard accents of English) in which a /əz/ suffix is added to words that end in /s/. For example, the plural of 'class' and 'dress' are /klɑsəz/ and /drɛsəz/ in standard forms of English. The question is: how do these kinds of Singapore talkers who regularly reduce consonantal clusters form plurals in words like 'tasks' and 'lists'? Since their singular productions end in /s/ (/tɑs/,/lɪs/) and since the pluralisation rule requires an /əz/, they should produce /tɑsəz/ and /lɪsəz/ (analogous to 'classes' and 'dresses') if it is the phonemic /s/ which is responsible for plurals in /əz/.

But these Singapore English talkers do no such thing: their plural forms of 'tasks' and 'lists' are the same as their singular forms i.e. /tɑs//lɪs/ even though they do produce the plural forms /klɑsəz/ and /drɛsəz/ for 'classes' and 'dresses'. How can we explain this?

The Generative Phonology solution would be to propose that the underlying forms of 'task' and 'list' in this dialect of Singapore English are /tɑsk/ and /lɪst/ i.e. with a full consonantal cluster that is not pronounced. Or from another point of view, these talkers' mental representations of these words -- that is, the way in which these words are stored in their mental lexicons -- include phonological forms (final /sk/, final /st/) that are never pronounced (by them). Generative Phonologists would then model the actual pronunciations of the singular and plurals in terms of phonological rules, as follows:

	'task'	'tasks'
underlying representation	tɑsk	tɑsk+s
cluster simplification	tɑs	tɑs+s
output (phonetic form)	tɑs	tɑs

Therefore, because Singapore English talkers 'know' that 'task' really has a final /k/ (even though they do not pronounce it), they do not add the plural suffix /əz/ (which is reserved for words like 'dance' which have a final /s/), but the plural suffix /s/, analogously to words that end in a final voiceless non-sibilant consonant ('tap', 'block' etc. which form plurals by adding/s/ thus /tæps/,/blɒks/ etc.).

The significance of this example (and there are many others like it) lies not so much in the details but rather in the idea that the way in which the pronunciation of words is stored in the mental lexicon may be a good deal more abstract than the phonemic representation of the actual pronunciations would suggest. If we accept this premise, then we must also accept the idea that there are phonological rules that link these often highly abstract underlying forms to the phonetic forms (or 'surface' forms, to use terminology from Generative Phonology) because otherwise we cannot explain how underlying forms are related to pronunciation (this is exactly parallel to our earlier phonemic/phonetic distinction: once we represent words phonemically, we have to have rules that fill in the redundant or predictable aspects of pronunciation like aspiration; the difference in the Generative Phonology model is that the underlying forms that are being proposed are more abstract than phonemic forms -- resulting in many more rules to explain the predictable and redundant aspects of pronunciation -- and they lay much greater emphasis on the claim that these underlying forms are in some sense 'psychologically real' i.e. part of the talker's linguistic competence).

http://clas.mq.edu.au/phonetics/phonology/generative/index.html