The extemporaneous speech. Extemporaneous speeches are planned, prepared,and rehearsed but not written in detail.Professionals use the extemporaneous style.Simple cues written on small index cards may provide enough material for the speaker to talk meaningfully for long periods Familiarity with the material makes this style effective.Instructors use it because material may be adapted to different class situations, just as public speakers may adapt their material to different audiences. The extemporaneous speech. Extemporaneous speeches are planned, prepared, and rehearsed but not written in detail. Professionals use the extemporaneous style. Simple cues written on small index cards may provide enough material for the speaker to talk meaningfully for long periods. Familiarity with the material makes this style effective. Instructors use it because material may be adapted to different class situations, just as public speakers may adapt their material to different audiences