Wednesday, October 8, 2008

About Syntax and Phrase Structure Rules







In the following lines we introduce a modest explanation of syntax and phrase structure rules:
At first we are starting with Syntax:
What is Syntax?
• "Syntax is the study of the principles and processes by which sentences are constructed in particular languages. Syntactic investigation of a given language has as its goal the construction of a grammar that can be viewed as a device of some sort for producing the sentences of the language under analysis."
(Noam Chomsky, Syntactic Structures, 1971)


• Another definition is that syntax describes the selection and order of words that make well-formed sentences and it does so in as general a manner as possible so as to bring out similarities among different sentences of the same language and of different languages and render them explainable. Since sentences are not just complex objects but symbolic objects that convey meanings, syntactic rules also need to account for the relationship between strings of word meanings and the entire sentence meaning, on the one hand, and the relationship between strings of word forms and the entire sentential phonetic form, on the other.

We cannot talk about syntax without mentioning the three grammar approaches which are:

First: Perspective approach
Refers to the structure of a language as certain people think it should be used. So, it is a view of grammar which sets out rules about the proper use of language.
Examples of prescriptive rules for English sentences are:
 You must not split an infinitive. '' to boldly go ''
 You must not end a sentence with a preposition
 You must say '' it's I'' instead of '' it's me''.
Therefore, according to this approach grammar is viewed as a set of normative rules; rules that tell us how we ought to speak and write.

Second: Descriptive approach It attempts to describe the regular structure of the language as it is used, not according to some view of how it should be used. In fact, these are rules that state what we in fact say. Analysts of this approach believe that what is correct and what is incorrect is ultimately a matter of what is accepted by society, for language is a matter of conventions within society. Thus, if everyone says '' it's me'' then surely '' it's me'' is correct English.

However, most of the rules of the traditional grammar that have been taught all over the years are prescriptive not descriptive. They prescribe forms that many of us would never normally use, and if we do, we feel we are ''speaking like a book''.

Both kinds of grammar are concerned with rules--but in different ways. Specialists in descriptive grammar (called linguists) study the rules or patterns that underlie our use of words, phrases, clauses, and sentences. On the other hand, prescriptive grammarians (such as most editors and teachers) lay out rules about what they believe to be the “correct” or “incorrect” use of language.

Third: Traditional approach
It only studied the particle of the sentence but not the structure of the whole sentence. So, it focuses more on subject verb agreement, gender, etc.

Interfacing with Grammar:

To illustrate these different approaches, let's consider the word interface. The descriptive grammarian would note, among other things, that the word is made up of a common prefix (inter-) and a root word (face) and that it’s currently used as both a noun and a verb. The prescriptive grammarian, however, would be more interested in deciding whether or not it is “correct” to use interface as a verb.

Here's how the prescriptive Usage Panel at The American Heritage Dictionary, 4th edition passes judgment on interface:

The Usage Panel has been unable to muster much enthusiasm for the verb. Thirty-seven percent of Panelists accept it when it designates the interaction between people in the sentence the managing editor must interface with a variety of freelance editors and proofreaders. But the percentage drops to 22 when the interaction is between a corporation and the public or between various communities in a city. Many Panelists complain that interface is pretentious and jargon.
Similarly, Bryan A. Garner, author of The Oxford Dictionary of American Usage and Style, dismisses interface as "jargon mongers' talk."
By their nature, all popular style and usage guides are prescriptive, though to varying degrees: some are fairly tolerant of deviations from Standard English; others can be downright cranky. The most irascible critics are sometimes called "the Grammar Police."
Though certainly different in their approaches to language, both kinds of grammar--descriptive and prescriptive--are useful to students.

In some, why do languages have syntactic rules? Because
• Most sentences consist of more than one word
• The selection and order of the words in sentences are not free
• The sum of the word meanings does not always equal the meaning of the entire sentence and the sum of the word forms does not always equal the phonological form of the entire sentence

The Value of Studying Grammar:
The study of grammar all by itself will not necessarily make you a better writer. But by gaining a clearer understanding of how our language works, you should also gain greater control over the way you shape words into sentences and sentences into paragraphs. In short, studying grammar may help you to become a more effective writer.
Descriptive grammarians generally advise us not to be overly concerned with matters of correctness: language, they say, isn't good or bad; it simply is. As the history of the glamorous word grammar demonstrates, the English language is a living system of communication, a continually evolving affair. Within a generation or two, words and phrases come into fashion and fall out again. Over centuries, word endings and entire sentence structures can change or disappear.
Prescriptive grammarians prefer giving practical advice about using language: straightforward rules to help us avoid making errors. The rules may be over-simplified at times, but they are meant to keep us out of trouble--the kind of trouble that may distract or even confuse our readers.
About Grammar & Composition attempts to integrate these two approaches to grammar--or, at the least, present them side by side. For instance, our discussion of the Basic Parts of Speech is primarily descriptive, while our lesson on Correcting Errors in Subject-Verb Agreement is obviously prescriptive.
Thus, the goal of this site is twofold: first, to deepen your understanding of the ways that the English language operates, and second, to serve as a practical guide as you work to become a more confident and effective writer. We look forward to hearing your suggestions on how we might do a better job of meeting both of these goals.
Phrase structure rules are a way to describe a given language's syntax. They are used to break a natural language sentence down into its constituent parts (also known as syntactic categories) namely phrasal categories and lexical categories (aka parts of speech). Phrasal categories include the noun phrase, verb phrase, and prepositional phrase; lexical categories include noun, verb, adjective, adverb, and many others. Phrase structure rules were commonly used in transformational grammar (TGG), although they were not an invention of TGG; rather, early TGG's added to phrase structure rules. A grammar which uses phrase structure rules is called a phrase structure grammar- except in computer science, where it is known as just a grammar, usually context free.

Definition:
Phrase structure rules are usually of the form A__ B C, meaning that the constituent A is separated into the two sub constituents B and C. some examples are
S__ NP VP
NP__ Det, N1
N1__ (AP) N1 (PP)
The first rule reads: An S consists of an NP followed by a VP. This means A sentence consists of a noun phrase followed by a verb phrase.
The next one: A noun phrase consists of a determiner followed by a noun.
And here is a more wide explanation:
• S__ NP VP
• NP Pro
(det) (adj) N (pp)


• VP__ (aux) v (NP) (pp) (adv p)
• PP __ prep NP
• Adj _ ( intens ) adj (pp)
• Det,
___ A, an, the
___ My, his, her
___ One, two, first, second
___ Mr., Miss, Mrs.
___ Few, little, much, all
___ Another, other
___ 's

There are three essential aspects of a sentence structure, the constituency of a sentence (the units into which it can be divide, such as words and phrases), the labeling of those units (with labels like 'noun' or 'adjective phrase'), and the ordering of those units relative to one another (for example, what comes before the verb, and what comes after, a crucial question in determining a sentence's meaning)…. A less obvious type of constituent is a phrase, which is a sequence of words which form a coherent group.
Associated with phrase structure rules is a famous example of a grammatically correct sentence. The sentence was constructed by Noam Chomsky as an illustration that syntactically but not semantically correct sentences are possible.

Colorless green ideas sleep furiously. Can be diagrammed as a phrase tree as in shape (1) 'press on the picture to see it clearly'
And here are some other examples of the sentence tree that helps analyzing the sentence structure:

 She looked for her key.
look at shape (2)'press on the picture to see it clearly'

 She works in an office
look at shape (3)'press on the picture to see it clearly'

 He will carry out a new project.
look at shape (4)'press on the picture to see it clearly'

 Tom and his friends know that I bought a present for Jane on her birthday.
look at shape (5)'press on the picture to see it clearly'

Of course we all agree on the sentence equation which is:
Sub + verb ± object ± subject complement ± adverb

And finally here are some reasons for saying that words are grouped into phrases
Meaning and phrase structure:
We begin by looking at the meaning of a sentence, and by focusing on a sentence (1) which is ''ambiguous'' that is, it has more than one possible meaning
(1) I was reading the letter to john
Before you go on decide what the two possible meaning of this sentence are
This sentence might mean:
(a) That there was a letter addressed to John which I was reading (perhaps to myself)
Or it might mean:
(b) That there was a letter (to me, perhaps) which I was reading aloud to John
We might say that there are two different sentences which look exactly the same (they both look like (1)), though they mean different things. Here we need to look for a structural difference between them which is not so immediately obvious. This difference is to be found in the different ways in which the words are grouped into phrases.

• Replacement and phrase structure:
We'll start with replacement. The word it can replace one of two sequences of words in (1), either the letter to John, giving (2), or the letter, giving (3)
(2) I was reading it.
(3) I was reading it to john.
We have taken an ambiguous sentence, (1), and turned into two alternative non-ambiguous sentences.

• Movement and phrase structure
Movement gives the same results as replacement, for sentence (1). If we move the letter to John as a group, we end up with a sentence which has meaning (a):
(4) The letter to John was being read by me.
If on the other hand we move the pair of words the letter on their own, we get meaning (b). this corresponds to the structure in (3), since it involves the idea that the letter is a phrase on its own:
(5) The letter was being read by me to John.
Presented by:
Sarah Nabil Abd El Aziz Mohammed
supervisor:
Dr. Mona Eid

No comments: