The boy wanted to say something else other than “Thank you, m’am” to Mrs. Luella Bates Washington Jones, but he couldn’t do so as he turned at the barren stoop and looked back at the large woman in the door.
Rather than choking on unspoken words, and merely saying, "Thank you ma'am," Roger may have wished to say, "I appreciate not only the meal, but the fact that you did not condemn me for my act, you did not preach to me, you told me you, too, have done bad things, and you showed real feelings for me, not pity."