In JL Austin’s theory of speech acts, an illocutionary act
is any utterance by which the speaker performs a certain action. Examples of
such action can be an argument, a question, a promise, an order, an apology
etc. in other words, an illocutionary act is
the act performed by the act of speech.
The illocutionary act includes the locutionary act, for example the sentence “it is raining”. But
it becomes an illocutionary speech act when it is performed
for example in order to alert someone to the fact that it is raining outside,
thus affecting his considerations or actions.
In other examples the illocutionary act can contradict the locutionary
act. Take for example the statement: “I am dead tired”. The speaker does not
mean the he is actually dead, but wants the listener to understand the he is
extremely tired.
In order to give good examples of illocutionary acts take
the meaning ingredient of a locutionary act and add the aspect of a receiver of
that meaning, that is the object of the speech act.
read further:
Examples of perlocutionary acts
see also: illocutionary force
Summary of How to Do Things With Words by J.L.Austin