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."
Chances are that Mrs. Jones has displayed more genuine feeling in the short time that Roger has been with her than his own family has. From the very beginning, Mrs. Jones demonstrates motherly understanding, rather than a judgmental attitude, even though she has "kicked him right square in his blue-jeaned sitter.”. The emotional position that she takes by inviting him into her home, trusting him to not touch her purse again, talking to him as though he were her own child-- “Eat some more, son”--touches Roger emotionally. In fact, this truly Christian charity exhibited by Mrs. Jones is what causes Roger to choke on his words as he is so deeply touched. By moving him emotionally, Mrs. Jones, also, has probably done more to reform Roger than any one else.