Chapters 8 to 13

Huck can tell the two men aren't royalty by their speech, incorrect information, and dress.

It didn't take me long to make up my mind that these liars warn't no kings nor dukes at all, but just low-down humbugs and frauds. But I never said nothing, never let on; kept it to myself; it's the best way; then you don't have no quarrels, and don't get into no trouble. If they wanted us to call them kings and dukes, I hadn't no objections, 'long as it would keep peace in the family; and it warn't no use to tell Jim, so I didn't tell him.

This is a Chapter 19 question.