My nearly 9 mo old until recently would imitate - and try to get you to imitate - by dancing (shaking his head) and by bibbling his mouth. He'd also dance to music.
But he's stopped doing these things and responding if you do them.
He does copy (as best he can) sounds you make and there is a lot of back and forth babble. He is generally very happy, engaged and sociable. But I'm worried he's lost skills he had? Is this regression or is it just a baby thing where they get bored of something?