I have a 4th grader that whines and uses "baby talk" regularly. I thought is was attention seeking at first, so I would ignore the behavior. Depending on the situation I would either walk away from her tantrum or continue our conversation. If I walked away, she would just pout and whine more if I tried to re-engage. It has become more frequent and more intense as the school year progresses. I then thought it might be escape from undesired work, so I tried to assess it by allowing her the opportunity to take a break of her choice. She would then whine that she did not want to leave. We have talked about how 4th graders act and she is reminded regularly, but it just makes her more upset and start a temper tantrum. Any suggestions?
Have you tried to record her reading or talking and playing it back for her. I had a student who did this and when I started recording them reading they noticed and commented in their own voice and volume. It was not immediate but eventually they did use a more appropriate tone.