He had a lot of pre-canned answers he could choose from. When he had to craft a new response, he had a lot of pre-assembled phrases which could be combined together. Creating an entirely new answer took more time. The program he used was actually pretty sophisticated, and was updated throughout his life.
Random fact: I nearly tripped over him once in the aisle of a darkened lecture theater. I looked back to see who was the idiot sprawled in the aisle like that, and my head pretty much exploded.