Does Boo Radley say anything in the novel?
He does indeed. He speaks just five words in one of the very last pages of the book, in chapter 31. We pick up the story after Boo has saved Jem and Scout from a crazed Bob Ewell. Scout and Boo are in Jem's room, and Jem lies sleeping soundly on the bed. Scout gives a somewhat hesitant Boo permission to stroke Jem's hair. Jem wouldn't let him do it if he were awake, not in a million years, but as he's asleep then it's no problem. Boo gently puts his hand on Jem's hair. He says nothing, but Scout understands his "body English," as she calls it, and feels his hand tighten against hers, indicating that he wants to leave.
Scout accompanies Boo to the front porch of the Finch residence, holding his hand. Suddenly, Boo stops and in a barely audible whisper, says:
Will you take me home?
Scout walks with Boo up to his porch. He slowly releases his hand from Scout's grasp and closes the door behind him. And that is the last time Scout ever sees him.