What can be some of the causes/reasons that a child (in the 7-year-old range) to speak in a silly voice and in a silly way, more than an average child? I don't know how to be more specific by silly voice and in a silly way, but I mean that the child speaks with a different voice, usually mimicking a spoiled 2-year-old in a way that is not the natural way that he usually speaks and it is pretty annoying and not very likable. It happens very often when the child communicates with grown ups. I am guessing it can be an attempt to draw attention or be liked more but I'm not a psychologist so I thought I'd ask.
What are some of the causes of this type of behavior in children, and what are some of the cures for it?