She spoke extemporaneously, and "brought down the house".
"Epistles-from-Pap-Letters-from-the-man-known-as-The-Will-Rogers-of-Indiana"
Durham, Andrew Everett
Many who were present, could scarcely believe that the children spoke extemporaneously.
"A Practical Enquiry into the Philosophy of Education"
James Gall
4. Select some subject with which you are familiar and test your fluency by speaking extemporaneously.
"The Art of Public Speaking"
Dale Carnagey (AKA Dale Carnegie) and J. Berg Esenwein