None of the members of the Radley family really have much to say in To Kill a Mockingbird. Boo has one only line--"Will you take me home?" at the end of the story--and Mr. and Mrs. Radley never say a word. As for Nathan, at least he responds to Jem and Scout when they speak to him on the street, unlike his father. Nathan's most memorable quote is actually spoken by Miss Stephanie, who tells the children after their unsuccessful raid on the Radley's back porch that he
"Says if anybody sees a white nigger around, that's the one. Says he's got the other barrel waitin' for the next sound he hears in that patch... be it dog, nigger or--Jem Finch!" (Chapter 6)
Nathan's only direct quotes come in Chapter 7 when Jem asks him about the cementing of the knothole.
"Morning, Jem, Scout," said Mr. Radley, as he went by.
"Mr. Radley," said Jem. "... ah--did you put cement in the hole in that tree yonder?"
"Yes," he said. "I filled it up."
"Why'd you do it, sir?"
"Tree's dying. You plug 'em with cement when they're sick. You ought to know that, Jem."