The Discourse Functions of Sentences

Sentences may be classified according to their use in discourse. We recognise four main sentence types:

• declarative
• interrogative
• imperative
• exclamative

Declarative

Declarative sentences are used to convey information or to make statements:

David plays the piano
I hope you can come tomorrow
We've forgotten the milk

Declarative sentences are by far the most common type.

Interrogative sentences are used in asking questions:

Is this your book?
Did you receive my message?
Have you found a new job yet?

The examples above are specifically YES/NO INTERROGATIVES, because they elicit a response which is either yes or no.

ALTERNATIVE INTERROGATIVES offer two or more alternative responses:

Should I telephone you or send an email?
Do you want tea, coffee, or espresso?

Yes/no interrogatives and alternative interrogatives are introduced by an auxiliary verb.

WH- INTERROGATIVES, on the other hand, are introduced by a wh- word, and they elicit an open-ended response:

What happened?
Where do you work?
Who won the Cup Final in 1997?

Questions are sometimes tagged onto the end of a declarative sentence:

David plays the piano, doesn't he?
We've forgotten the milk, haven't we?
There's a big match tonight, isn't there?

These are known as TAG QUESTIONS. They consist of a main or auxiliary verb followed by a pronoun or existential there

Imperative

Imperative sentences are used in issuing orders or directives:

Leave your coat in the hall
Give me your phone number
Don't shut the door
Stop!

Tag questions are sometimes added to the end of imperatives:

Leave your coat in the hall, will you?
Write soon, won't you?

Exclamative sentences are used to make exclamations:

What a stupid man he is!
How wonderful you look!

The four sentence types exhibit different syntactic forms, which we will be looking at in a later section. For now, it is worth pointing out that there is not necessarily a one-to-one relationship between the form of a sentence and its discourse function. For instance, the following sentence has declarative form:

You need some help

But when this is spoken with a rising intonation, it becomes a question:

You need some help?

Conversely, rhetorical questions have the form of an interrogative, but they are really statements:

Who cares? ( = I don't care)