The “directive function” means that language may be used to get the hearer to do something. Most imperative sentences perform this function, e. g., “Tell me the result when you finish.” Other syntactic structures or sentences of other sorts can, according to J.Austin and J.Searle’s “indrect speech act theory”(see Hu Zhuanglin et al.,pp271-278) at least, serve the purpose of direction too, e.g., “If I were you, I would have blushed to the bottom of my ears!”
1.13.What is the informative function?
Language serves an “informational function” when used to tell something, characterized by the use of declarative sentences. Informative statements are often labelled as true(truth) or false(falsehood). According to P.Grice’s “Cooperative Principle”(see Hu Zhuanglin et al., pp282-283), one ought not to violate the “Maxim of Quality”, when he is informing at all.
1.14.What is the interrogative function?
When language is used to obtain information, it serves an “interrogative function”. This includes all questions that expect replies, statements, imperatives etc., according to the “indirect speech act theory”, may have this function as well, e.g., “I’d like to know you better.” This may bring forth a lot of personal information. Note that rhetorical questions make an exception, since they demand no answer, at least not the reader’s/listener’s answer.
1.15.What is the expressive function?
The “expressive function”is the use of language to reveal something about the feelings or attitudes of the speaker. Subconscious emotional ejaculations are good examples, like “Good heavens!” “My God!” Sentences like “I’m sorry about the delay” can serve as good examples too, though in a subtle way. While language is used for the informative function to pass judgement on the truth or falsehood of statements, language used for the expressive function evaluates, appraises or asserts the speaker’s own attitudes.
1.16.What is the evocative function?
The “evocative function” is the use of language to create certain feelings in the hearer. Its aim is , for example, to amuse, startle, antagonize, soothe, worry or please. Jokes(not practical jokes, though) are supposed to amuse or entertain the listener; advertising to urge customers to purchase certain commodities; propaganda to influence public opinion. Obviously, the expressive and the evocative functions often go together, i.e., you may express, for example, your personal feelings about a political issue but end up by evoking the same feeling in, or imposing it on, your listener. That’s also the case with the other way round.
1.17.What is the performative function?
This means people speak to “do things” or perform actions. On certain occasions the utterance itself as an action is more important than what words or sounds constitute the uttered sentence. When asked if a third Yangtze bridge ought to be built in Wuhan, the mayor may say “OK”, which means more than speech, and more than an average social individual may do for the construction. The judge’s imprisonment sentence, the president’s war or independence declaration, etc., are performatives as well(see J.Austin’s speech Act Theory, Hu Zhuanglin, ecal.,pp271-278).