How do speech acts such as promises and requests use language to perform actions?

In the philosophy of language, speech act theory posits that language is not merely for making descriptive statements that are true or false, but is a tool used to perform social actions. Developed by J.L. Austin and refined by John Searle, this theory explains how utterances like promises and requests function as actions.123

How Speech Acts Function

Speech acts are defined by their "illocutionary force"—the specific action performed in the act of speaking.14

• Directives (e.g., requests): These acts have a "world-to-word" direction of fit, where the speaker attempts to get the hearer to perform an action. For example, a request expresses the speaker's desire that the hearer do something.3
• Commissives (e.g., promises): These also possess a "world-to-word" fit, but in this case, the speaker undertakes an obligation to make the world match their words by performing a future action.3

Conditions for Success

For these acts to be effective, they must meet specific conditions. Austin noted that the institutional setting and the speaker's authority are often crucial for an act to "count" as intended. Searle further systematized this by identifying rules for "sincerely and non-defectively" performing acts, such as the requirement that a person making a promise must genuinely intend to carry it out.143