I discovered that I'm much more articulate at writing than speaking. In verbal communication it always seems to follow the same inexpedient process:
(1a) Unconsciously utter a generic response. (I've been using "Okey-dokey, doctor Jones" a lot recently.)
(1b) Or repeat last word(s) I heard (Like what people do when they don't know what is being talked about. In movies, at least.)
(2) Pause for several seconds to think and process what was said and generate an appropriate response. Usually with a silence filler like a long "Uhmmmmmmm..."
(3) Respond with with around 70% of the content you thought of, forgetting about the other 30% until later, when the conversation has been dropped.