What type of speech typically requires preparation and planning before delivery?

An extemporaneous speech is characterized by its nature of being prepared in advance but delivered in a conversational manner, often based on notes or an outline. This type of speech allows the speaker to express their points clearly and effectively while maintaining flexibility to adapt to the audience's reactions or questions during delivery. The preparation focuses on understanding the subject matter, organizing thoughts, and practicing the delivery style, which enhances the overall effectiveness of the communication.

In contrast, impromptu speeches are delivered without prior preparation, requiring quick thinking and spontaneity. Memorized speeches involve reciting a pre-written script without notes, and while they require initial preparation, the delivery does not permit the same level of adaptability during the presentation. Informal speeches are typically unstructured and may arise in casual settings, lacking the planning and organization seen in extemporaneous speeches. Thus, extemporaneous speech stands out for its necessary balance of preparation and adaptability for successful delivery.