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RULES

This document discusses phrase structure (PS) rules, which capture a speaker's knowledge about the permissible structures in their language. PS rules are a finite set of templates that generate trees to represent sentences. The document provides examples of PS rules for English that specify the components of phrases like noun phrases and verb phrases, as well as the linear order of those components. It demonstrates how additional rules are needed to generate trees for sentences with different structures, like sentences containing prepositional phrases, verbs alone, or embedded clauses.

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85 views3 pages

RULES

This document discusses phrase structure (PS) rules, which capture a speaker's knowledge about the permissible structures in their language. PS rules are a finite set of templates that generate trees to represent sentences. The document provides examples of PS rules for English that specify the components of phrases like noun phrases and verb phrases, as well as the linear order of those components. It demonstrates how additional rules are needed to generate trees for sentences with different structures, like sentences containing prepositional phrases, verbs alone, or embedded clauses.

Uploaded by

hasna
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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The information represented in a PS tree can also be represented by

another formal device: phrase structure (PS) rules. PS rules capture the knowledge
that speakers have about the possible structures of a language. Just as a speaker
cannot have an infinite list of sentences in her head, so she cannot have an infinite
set of PS trees in her head. Rather, a speaker's knowledge of the permissible and
impermissible structures must exist as a finite set of rules that generate a tree for
any sentence in the language. To express the structure given above, we need the
following PS rules:
1. S  NP VP
2. NP  Det N
3. VP  V NP
Phrase structure rules specify the well-formed structures of a language
precisely and concisely. They express the regularities of the language and make
explicit a speaker's knowledge of the order of words and the grouping of words
into syntactic categories. For example, in English an NP may contain a determiner
followed by a noun. This is represented by rule 2. This rule conveys two facts:
A noun phrase can contain a determiner followed by a noun in that order.
A determiner followed by a noun is a noun phrase.
You can think of PS rules as templates that a tree must match to be
grammatical. To the left of the arrow is the dominating category, in this case NP,
and the categories that it immediately dominates-that comprise it-appear on the
right side, in this case Det and N. The right side of the arrow also shows the linear
order of these components. Thus, one subtree for the English NP looks like this:
NP

Det N
Rule 1 says that a sentence (S) contains (immediately dominates) an NP
and a VP in that order. Rule 3 says that a verb phrase consists of a verb (V)
followed by an NP. These rules are general statements and do not refer to any
specific VP, V, or NP. The subtrees represented by rules 1 and 3 are as follows:
A VP need not contain an NP object, however. It may include a verb
alone, as in the following sentences:
 The woman laughed.
 The man danced.
 The horse galloped.
These sentences have the structure:

Thus a tree must have a VP that immediately dominates V, as specified by


rule 4, which is therefore added to the grammar:
4.VP  V
The following sentences contain prepositional phrases following the verb:
The puppy played in the garden.
The PS tree for such sentences is

To permit structures of this type, we need two additional PS rules, as in 5


and 6.
5. VP  V PP
6. PP  P NP
Another option open to the VP is to contain or embed a sentence. For
example, the sentence "The professor said that the student passed the exam"
contains the sentence "the student passed the exam." Preceding the embedded
sentence is the word that, which is a complementizer (C). C is a functional
category, like
Aux and Det. Here is the structure of such sentence types:

To allow such embedded sentences, we need to add these two new rules to
our set of phrase structure rules.
7. VP  V CP
8 . CP  C S
CP stands for complementizer phrase. Rule 8 says that CP contains a
complementizer such as that followed by the embedded sentence. Other
complementizers are if and whether in sentences like I don't know whether I
should talk about this. The teacher asked if the students understood the syntax
lesson.

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