DS went through a repetition stage like that. He seems to have passed that, but still repeats stuff when he gets excited. He repeats anything DH says to him when I'm around, and vice versa. 'Daddy just said ....' Yes, I know, I'm right here. I can hear!

I too think its part of DS' coping strategy for sensory issues - he talks to himself constantly, and I think it's to 'fill in the empty space', iykwim. If there's a loud noise, he yells until it's over. White noise helps here - having the radio/music on. So on 'those days', we have a lot of music playing! Today I mini-vac'd the entire house just so I could NOT hear his voice for a few minutes!