What is the term for a speech delivered with little or no preparation?

The term for a speech delivered with little or no preparation is extemporaneous. This type of speech is characterized by its spontaneous and informal style, where the speaker relies on their knowledge of the topic and engages with the audience without a scripted text. The ability to think on one's feet and communicate effectively in the moment is a valuable skill in many contexts, including agriculture and public speaking.

Prepared addresses, on the other hand, involve a level of planning and scripting, making them distinct from extemporaneous speeches. Impulsive speech may suggest a lack of thought or consideration prior to speaking, which does not align with the idea of being able to articulate thoughts coherently on a subject matter. Draft presentations indicate the initial stages of preparing a speech rather than executing it in a spontaneous manner, which further clarifies why extemporaneous is the most fitting term for a speech delivered with little to no advance preparation.