What is NOT one of the three basic purposes of a formal speech?

The three basic purposes of a formal speech typically include informing, entertaining, and persuading an audience. Each of these serves a distinct role in communication. Informing involves providing the audience with new information or insights on a topic. Entertaining aims to engage the audience and evoke positive feelings, while persuading focuses on convincing the audience to adopt a certain viewpoint or take action based on the presented arguments.

Describing, while an important aspect of communication, does not qualify as one of the main purposes of a formal speech. Descriptive elements can be incorporated into speeches, but they serve more as a means to support the primary functions—informing, entertaining, or persuading—rather than constituting a separate purpose in itself.