Acts performed when words are uttered. J. L. Austin claimed that the complex act of uttering words involves various simple component acts.
There is, first, the locutionary act (saying words). This involves a phonetic act (making noises), a phatic act (using grammar) and a rhetic act (using meaningful words).
Next there is the illocutionary act (act done in uttering words, for example, promising or stating).
Finally there is the perlocutionary act by which we cause effects, for example, embarrassment, in other people by our words. Austin and others have believed that the study of speech acts may clarify problems about meaning, reference, and so on.
From A Dictionary of Philosophy (Rev. 2nd ed.) ed. Antony Flew (St. Martin’s, 1979), 333.