Final answer:
A speech that is planned and researched but not scripted and allows for variation during the presentation is called extemporaneous.
Step-by-step explanation:
A speech researched and planned ahead of time, but for which the exact wording is not scripted and is expected to vary during actual presentation, is known as extemporaneous speaking. While elements such as an outline and research are integral to the speech, it is the skill of the speaker to adapt their delivery in the moment that distinguishes extemporaneous speaking from other forms such as scripted, impromptu, or memorized speeches. Similar to academic writing, a successful speaking event often requires a speaker to engage their audience with clear communication, an organized presentation of ideas, and an ability to connect with the audience on a personal level, regardless of whether the speech is live or recorded for a video-sharing social media platform.