what might the pilgrims say to him

I believe the pilgrims would say things that help him in his description of them in the prologue. For example one of the holy men makes the point that he does not have time to go by the rules of his order (of St. Francis) because he has better things to do. They would have to describe, for example, what they have concerns about; the nun, for example, is very sympathetic to small creatures which she would have to refer to or else Chaucer could not write that detail about her. He finds out that the Reeve, for example, cheats his master, and watches the interaction between the characters to learn about them. He uses the prologue to report all of this information.