Aspeech that is fully prepared and outlined in advance but that is delivered from a brief set of notes or speaking outline is called a(n) speech.

I believe the answer is: extemporaneous speech

The speaker who did extemporaneous speech usually being appointed spontaneously without any prior knowledge.
example of the situation would be in things such as award ceremony where the winners is still kept a secret until the event, religious social settings, etc.

Rehab i’m not sure but i hope this