Mulan,
My youngest daughter displays these symptoms. Her father was like that also. The main problem with this disease is IMPULSIVENESS. They start doing these things (interrupting, chattering, bossing, etc) without thinking about it first. Ridiculing them only makes it worse, because it hurts their self-esteem. Which is probably what has happened to her as she was growing up.
It's not easy to live with, believe me! My little one is five years old, and let me tell you, she talks a blue streak when people are around. Tells everything, and I do mean EVERYTHING she knows. My hubby once in awhile will just plain get tired of hearing her voice, and tells her, "I don't want to hear your voice for the next 15 mins!"
because you can't hold a conversation without her joining in with her .02! I realize she's slightly hyperactive, but that's the least of her problem. Impulsiveness is where it begins. No brakes. No sense to know when to stop. And she is the most curious human being I've ever known. Listens to everything and absorbs like a sponge! Highly intelligent, but waaaaaay too impulsive. Interrupting people and being extremely impatient are her hallmarks. We have to constantly remind her and repeat to her to control these behaviors.
On the more positive side, she's very sunny in her usual disposition, very joyful, loves nature, and is very loving. She's just talkative and opinionated! lol
My suggestion is to either you or your son have a chat with her, and let her know that certain behaviors are highly annoying and will not endear her to people.
What I have found that helps with my little one is constant repetition. She is so impulsive that she moves before she thinks. It can tire a person out just trying to be one step ahead of her! lol She has a very controlling personality. Her father was one to throw tantrums like a child and demand his way all the time. She'll use the same expressions and has the same attitude, and I know it can be very difficult to deal with on a daily basis!
Good luck, and I hope things get better!
RCat