Does Tortoise head for example, really believe that he has something intelligent to say?
Yes.
Do they know they are lying?
Not mutually exclusive. The best liars are the ones who believe their own lies. People have an amazing ability to do this, and to compartmentalize their thinking.
Sociopaths, Narcissists, Pathological/Compulsive Liars, people with personality disorder, ect. are good examples. Take any successful "prophet" for example. I doubt any of them are simply lunatics, nor are any of them simply liars. It takes a combination of the two. The trick is to be as intellectually dishonest with yourself as you are with others.
So in a sense, no they dont know they are lying when they lie, even when they are consciously lying.