The structural types of sentences described in the previous section do not have connections with any special meanings. Yet if we take a sentence and start changing its structure we may observe that the sentences received as a result of transformations possess some common and altering meanings. Lets take a simple sentence:
1) John will come tomorrow>
2) Will John come tomorrow?>
3) Come tomorrow, John!
Comparing these sentences we can see that all of them describe one and the same event – John's arrival at a certain place. But the first sentence presents this event as a fact that is to happen, and the speaker informs the listener about it.. The second sentence shows that the speaker wants to know if the event will become a fact and asks the listener to confirm or to negate it. The third sentence also shows that the speaker demands something of the listener, this time that the listener should do so that the event should become a fact. This difference of meanings corresponds to the difference of the form of the sentences. It means that we observe here an opposition of forms reflecting a certain meaning and discovered a grammatical category-The semantic basis of the categoryor in other words its catgorial meaning is influence of the speaker upon the listener. This basis corresponds to the illocutionary meaning of speech acts. If we compare these meaning with the illocutionary classes we can see that they reflect two most frequent classes — informatives and directives. The first sentence embodies the informative types of speech acts and is called declarative. The other two belong to the directives and formally differentiate direction for an action (the third sentence ) and has the name of imperative or direction for a special type of action — informing the speaker (the second sentence) and is termed interrogative.
The formal features of these sentences include modifications of its predicate structure and use of special types of intonational patterns. It is necessary to note that modifications of the predicate are not absolutely necessary, while the intonational features can differentiate the communicative types by themselves. It means that adequate grammatical description of sentences should include indication of their phonetical properties.
We may expect that other classes of speech acts should also be reflected in the system of sentences as grammatical categories. And we can really find an opposition of so called exclamatory sentences to non- exclamatory ones. The stronger emotive meaning of the sentences are shown by alterations either in order of words (A nice day it was!), or by omission of some important element (How kind of you!), or by altering the predicate (Do come tomorrow!). Still all these features are additional because the formal indicator of the type of emotional colouring od the sentence is prosody — specific modifications of the tempo, rhythm, tune and volume of the sound.
The other two classes of illocution do not find their reflections in the communicative types of sentences. We should stress two more differences of the communicative categories of sentences and the illocutionary components of speech acts. The first is the very fact that the illocutionary components make groups of different units – classes, while the communicative features make semantic and formal variants of sentences – category forms of the respective communicative categories. The second is that the categorial meaning of the communicative categories of sentences are very general and indicate only the most essential elements of activity (informing, demanding information and instructing) and are directly shown by the differences in the form of what can be treated as an analogue of the propositional component, while the speech acts are more specialised and only indirectly reflected in the form of their propositional components. Because there is no direct correspondence between the form and the illocutionary component of the speech act the sentences having specialised communicative form are often used in utterances the pragmatic meanings of which may even be in contrast with the communicative meaning of the sentence. Declarative sentences can be used in directives, as is the norm in written orders. Interrogative sentences are also very often can form directive speech acts. Interrogative sentences may sometimes mean statements as in the case of rhetoric questions. Imperative sentences on the contrary are almost exclusively limited to forming all sorts of directive speech acts starting with orders and ending with pleadings, though self imposing act of promise is never found in the form of imperative sentences.
This phenomenon, use of a smaller unit in a larger one to perform an unusual for it function is a widely spread case. It is basis of the so called syntagmatic meanings of grammatical forms and we shall meet it not once in our description of the grammatical system of English.