TG grammar attempts to describe actual and potential sentences. It aims at generating all and only sentences of a language. It is able to detect ambiguity. If a structure is understood in two ways by the native speaker, a strong grammar should assign structural descriptions to the same structure.
Instead of relying on tree diagrams to represent how sentences were constructed from individual morphemes, Chomsky was concerned to discover the patterns by which one sentence could be transformed into another. In TG grammar we now have a set of rules to work from, to transform kernel sentences (i.e., the original from which we make the transformations) into others and we have a way of dealing with both the embedding problem and the ambiguity problem.
The Problem of Embedding
For example, if we take a sentence such as The man who was in the bar spoke to me, the structural linguistics analysis would either have lines crossing each other or result in the kind of block diagram.
However, we can look for the kernel sentences which make it up and then work out the transformation rules.
The kernel sentences are:
- The man spoke to me.
- The man was in the bar.
The transformation rules are:
- Place the second sentence after the first NP in the first sentence. That gives us:
The man the man was in the bar spoke to me
- Replace the second NP with who. That then gives us:
The man who was in the bar spoke to me
The Problem of Ambiguity
The often-cited example of an ambiguous statement which transformational-generative grammar can deal with is:
The shooting of the hunters was terrible.
The ambiguity, of course, is that we don’t know whether the hunters were bad shots or whether they were shot. Here’s how TGG can unravel the problem.
The key noun phrase is the shooting of the hunters. This noun phrase can come from two possible kernel sentences:
- The hunters shot (something).
- The hunters were shot.
Once we know which of the kernel sentences produced the noun phrase we have disambiguated the sentences. This is an example of the workings of deep structure. ie., the structure of the sentence which derives from the nature of the kernel sentences and is below the surface structure traditionally analysed in structural linguistics. There are two possible deep structures here identifiable from the two possible kernel sentences.
Another example, Flying planes can be dangerous.
The sentence is ambiguous for we cannot tell what is dangerous, the planes that fly or the act of flying planes. We can, however, resolve this ambiguity by showing that the same sentence can be analysed as being transforms from two different sets of kernel sentences. The present sentence can be derived from the following two different sets:
- Some people fly planes. This can be dangerous.
- Planes fly. They can be dangerous.
In the sentence, I spoke to the girl with a microphone, ambiguity can be explained by explaining the two sets of component sentences from which the ambiguous sentence has been derived.
- I spoke to the girl. The girl was with a microphone.
The second sentence is transformed into a prepositional phrase modifying the noun ‘girl’.
- I spoke to the girl. I spoke with a microphone.
The second sentence is transformed into a prepositional phrase modifying the verb ‘spoke’.
The sentence, Thank you for your paper and the presentation which I have now sent to the editor, is derived from the following two different sets:
- Thank you for your paper. Thank you for the presentation. I have now sent your paper to the editor.
The first two sentences are conjoined to form the first part of the sentence. The third sentence is combined with the earlier compound sentence after applying NP switch and relative pronoun replacement rules.
- Thank you for your paper. Thank you for the presentation. I have now sent the presentation to the editor.
The ambiguity results from the difference in the NP (as object) the relative pronoun refers to.
Thus TG grammar makes use of the concept of the deep structure by giving a different subject for each sentence. It gives more importance to the speaker’s competence than to his performance. It is not concerned with analysing that which is actually said but with establishing the rules concerning what can be said.
What is actually said by speakers of the language is called performance and is not the concern. What is possible for a speaker to say is called competence and is the concern.
According to the theory, then, what happens is that speakers of language work to an internalized set of rules from which they generate grammatically accurate language. The proper concern of grammar studies, then, is to find out what these rules are and that cannot be done solely by looking at what is said but by considering what can be said.