Syntax in TG
According to Chomsky's Standard Theory, the syntactic component in TG consists of two
parts: the Phrase Structure Rules (PS rules) and the Transformational Rules (T-rules).
In PS rules, symbols are used to label the abstract syntactic categories. The basic structure of
English sentences may be symbolized as
S → NP VP
S stands for "sentence", NP for "noun phrase", and VP for "verb phrase". The arrow is a
symbol for derivation and it reads, "to be rewritten as". The derivation may also be
represented by a labeled tree diagram:
S
NP
VP
Figure 4-4 labeled tree diagram
This basic structure may be expanded progressively by a series of PS rules as follows:
S → NP VP
NP → (D) (AP) N {PP, AP, S}
VP → (Aux) V {NP, PP, S}
AP → (Deg) A {PP, S}
PP → P {NP, S}
Here Aux stands for "auxiliary", D or Det for "determiner", Deg for adverbial of degree, AP
and A for "adjective phrase" and "adjective", and PP and P for "prepositional phrase" and
"preposition", etc. Round brackets are used to indicate that the category is optional in the
rule, and the categories in the curly brackets are optional choices. As the structure expands,
the tree also grows accordingly:
S
NP
D
VP
N
Figure 4-5 expanded tree diagram
V
NP
D
N
The labeled dots in the tree are called nodes, and the lines that connect them are referred
to as branches. The symbols that label the lowest nodes, such as "D+ N + V + D + N",
make up what is called the terminal string, which represents (only the abstract syntactic
structure of the sentence. Words are to be taken from the Lexicon and to be inserted into
the slots indicated by the symbols in the terminal string so as to make the sentence
meaningful. The Lexicon is a full list of words with information about their categories
(word classes) and subcategories such as count and non-count for nouns and transitive,
mono-transitive or ditransitive for verbs), and about their relevant semantic properties
that may restrict the selection of words. For example, in the Lexicon the information
concerning the, fox, eat, meat may include:
the
D (The word the is a determiner.)
fox
N +[animate] (The word fox is a noun. It is an animate being.)
eat
V +[ S +[animate] __ NP] (The word eat is a verb. It requires
an animate subject. It is mainly transitive and should be followed by a noun phrase.)
meat
N (The word meat is a noun.)
The above information guarantees that the selection and insertion of these words are
appropriate. As the PS rules and the Lexicon together make up what is called the Base,
the sentence "generated" from the Base may be presented as:
S
NP
D
The
N
VP
V
fox eat
NP
D
N
the
meat.
Figure 4-6 sentence "generated" from the Base
A sentence generated in this way from the Base is called the Deep Structure of the sentence.
It is a structured string of words, which contains the semantic information for the
interpretation of the sentence. T-rules are to be applied before we can get the Surface
Structure of the sentence, which is the final syntactic and phonological representation of
the sentence, the sentence uttered by the speaker. T-rules are the syntactic rules
according to which certain constituents of the sentence can be moved, deleted and added.
For example, if the "Passive T-rule", which involves switching the position of the two NPs
and introducing by and the auxiliary was, is applied, the surface structure of the generated
sentence can be
The meat was eaten by the fox. ,
If then we apply the By-deletion T-rule, we will get
The meat was eaten.
If we follow this up with another T-rule — the "Yes-no Question T-rule”, which moves
the auxiliary to the initial position, the sentence will become a question:
Was the meat eaten?
Similarly, Beautiful she is! is transformed from She is beautiful, and It is good to do exercise
is transformed from To do exercise is good. They are pairs of sentences that have the
same deep structures.
The distinction between deep and surface structures enables us to explain the difference
between the following pair of sentences, which appear to have the same surface structure
syntactically:
John is eager to please.
John is easy to please.
We can simply point out that they have two distinct deep structures and the syntactic
difference is obliterated by the application of certain T-rules. Their deep structures may be
roughly presented as:
S
NP
S
VP
V
Someone please John
A
is easy
Figure 4-7 deep structure
S
NP
N
John
VP
V
is
A
eager
S
John please someone
Figure 4-8 deep structure
A sentence with structural ambiguity can also be explained by giving two different deep
structures. For example, the ambiguous sentence
John likes dogs more than Mary.
has two distinct deep structure sentences:
John likes dogs more than Mary likes dogs.
John likes dogs more than John likes Mary.
Many new rules were proposed in Chomsky's writings of the 1980s and 1990s. The
proposals advanced are regarded as GB Theory (Government/Binding Theory). Some of
these new rules are introduced in the following discussion.
By a closer observation of the PS rules, one may find that many of the PS rules have a
similar formulation. For example, NPs always contains an N, PPs a P and VPs a V, etc. In
other words, XPs always contain an X, which stands for either N, or V, or A, or P. The X is
the head of the XP, and the other categories in the XP are there either for the specification
or complementation of the head X. While X is always present in the XP, the other categories
are optional. If we regard as the complement of the head X any category closely connected
with it, and as its "specifier" any category which is not related to it and does not always
consist of a complete phrase in its own right, many PS rules can be generalized as
XP→ (Specifier) X (Complement)
It is on the basis of this generalization of the "head-centered" characteristic of PS rules that
a new PS theory is developed. The theory is called X-bar Theory because in this theory
XP is replaced by "X-two-bar", an X with two bars over the category label, and the
intermediate X category only with complement after it is symbolized by "X-bar", an X
with one bar over the category label. The generalised PS rules in the X-bar Theory are:
_
X= → (specifier) X
_
X → X (complement)
Here we have bars on the right of the category label instead of over it only for
typographical convenience. As X= stands for any phrases, the above bar-marking can
apply to NP, VP, AP and PP. The PS rules resulted are illustrated as follows:
_
N_= →(D) (A=) N
N →N{P=, A=, S}
N=
_
D
N
N
P=
The
man
in the room
Figure 4-9
_
V=→(Aux)V
_
V →V{ N=, P=, S}
V=
_
Aux
V
V
N=
will see your father
Figure 4-10
_
A=→(Deg) A
_
A →A{P=, S}
A=
Deg
_
A
P=
A
very
angry with her
Figure 4-11
_
P=→(Adv)P
_
P →P{ N=, S}
P=
_
Adv
right
P
P
N=
behind
the tree
Figure 4-12
The X-bar Theory is extended to sentences by introducing a category Complementizer
(COMP) into the PS rules to indicate the subordinators of any dependent clauses, such as
that, which, who, whether, what, if, for, etc., or the inverted auxiliaries in yes-no questions.
The PS rule postulated is
_
S →(COMP) S
S →N= V=
For example, a dependent clause "... that I would be here" may be represented as:
S
N=
V=
_
_
N
N
he
V
V
S
COMP
said
Figure 4-13
_
S
that he would be here
a dependent clause
And a yes-no question, such as "Are you the new teacher":
S
COMP
_
S
are you t the new teacher
Figure 4-14
a yes-no question
The rule is also applied to sentences that have an empty COMP:
S
_
COMP
S
he is a new teacher
e
Figure 4-15 sentences that have an empty COMP
_
Now the above-mentioned PS rules that contain S, such as "V " → V {N=, P=, S}", can be
_
_
changed to "V → V {N=, P=, S }".
For example, the structure of the sentence The man told me that he wanted the book can
be described in the following tree diagram:
S
_
COMP
S
=
_
N
D
N
N
_
V
V
N
=
_
N
S
_
COMP
S
N
e
the man
told me
that he wanted the book
Figure 4-16
In order to make the top level of sentences conform to the X-bar requirement for the other
levels, COMP and INFL (inflection) are given the status of a "Complementizer Phrase"
and the head of an "Inflection Phrase". INFL includes Tense (one of "agreement" or AGR)
and Aux, which were both included in the V. So "S → N= V=" is now "S → N= INFL V=".
As I= stands for INFLP, S becomes I=to conform to the X-bar requirements:
=
= _
=
I_ → N I=
I→ IV
I
N
_
I
=
INFL
V
Figure 4-17
Then as C= stands for COMPP, "S→ COMP S" becomes
_
C=_ → (N=) C __
C _→ C I=
C=
N=
_
C ____
COMP
Figure4-18
I=
Now the XP Rule is really a general rule that can cover all phrase structure rules. Likewise,
a general rule is given to cover all the transformation rules. It is referred to as Move α ,
in which α (alpha) stands for any element that can be moved from one position to
another in the deep structure. After the application of Move a , certain constituents are
moved from their original positions. In order to present in the surface structure the semantic
information carried by these original positions in the deep structure, an "empty" category
"Trace", symbolized by t, is introduced to indicate the "trace" left behind in the place any
constituent formally occupied before the movement. This is already illustrated by the
example “Are you the new teacher" in the previous discussion.
The deep structure of the sentence What will Paul wear is Paul will wear what. To form a
question, what is moved to the initial position and will is also moved forward. The result
can be presented as: C=
C=
N=
what
C
_
I=
C
will
N=
_
I
V=
Paul I
t
wear
t
Figure
4-19
Trace is a phonetically null category, but it affects the semantic interpretation of| the surface
structure. Consider the following deep structure sentences:
a. which book have you read t
b. Teddy is the man (whom) I want to succeed t
c. Teddy is the man (whom) I want t to succeed
In the above sentences, t shows where the underlined constituents are in the deep structures.
The different positions of t in c and b show that there are two distinct deep structures for
the ambiguous sentence Teddy is the man I want to succeed, which can mean either c "I
want to succeed Teddy" or b "I want Teddy to succeed".