Final answer:
The speaker may describe a location, object, or person; explain an idea or how to operate something; or demonstrate a process. These speeches are usually organized according to a specific purpose and incorporate media, such as visuals or videos, to illustrate the content.
Step-by-step explanation:
In the context of common informative speech types, lengthy expository speeches are known as lectures. Such speeches explain, describe, or demonstrate in detail, and are often organized to cater to a specific purpose and audience understanding.
Examples include lectures that describe a historical event, explain scientific concepts, or demonstrate a process. Informative speeches tend to make use of various media like visuals or videos to enhance the audience's comprehension of the subject matter being presented.