Several months ago, we adopted a young dog from a shelter. She had not been trained by her previous owner, and at almost 18 months old, still wasn't housebroken. She knew she was supposed to do her business outside, yet she had accidents all the time. We figured out that the previous owner must have scolded her - she acted afraid and cowered when she pottied indoors, but something must have happened to reinforce the behaviour. We realized the negative attention (yelling/scolding) must have been the reinforcing factor that perpetuated the behaviour. So we started ignoring the accidents, and started rewarding the behaviour we wanted. Whenever she did her business outside, we hugged her and praised her: "What a good girl!! Good job!!" Within a week, the accidents stopped and she started letting us know when she wanted to go outside. We kept reinforcing the appropriate behaviour with praise - she loved the positive attention even more than the negative attention she'd had from the previous owner, and it was as if she wanted to elicit praise from us. She stopped other negative behaviour too, like tearing blankets and nipping at us as a greeting, when we rewarded appropriate behaviour with praise and attention.
Whenever they say something that arouses feelings of fear, guilt or anxiety in you or something that is simply none of their business, take a deep breath, IGNORE it and change the subject to something more appropriate.
Whenever they say something pleasant, loving and helpful, feel free to respond in kind.
It may take them a while to catch on, but they will eventually realize how to speak to you if they wish to have a response.