Receptive Language?

Two cute things that made me so hopeful- first, every speech therapist wants us to get Peter to imitate us, but he hadn't for so long. Then the "magic microphone" was suggested. This is where you use one of those spinning LED toys, and pretend it's voice activated. I was skeptical, but willing to try it. When we first tried it I said "ahhh" and lit the toy up while my voice was on, then I passed it to Peter- nothing. Then I demo'd it, then Sydney, then Samantha. After several silent turns Peter finally stated saying "ahhh" also!!  For anyone who has a normal hearing child this may seem really trivial to get excited about, but since my little guy had no way to hear himself before getting his cochlear implant,  now that he is starting to mimic sounds it shows that the technology is helping him!

The second thing happened today. At gymnastics I asked "where is Sydney?" I did not use sign, as I had Peter and other things in my arms. Peter held up two fingers and his thumb to his face and then pointed to where Sydney was sitting behind some other girls.  Those two fingers and thumb? It was the sign for BUG (Sydney's nickname, and the sign we use for her).

 Maybe he heard and understood me? Lately he has also been looking for and signing CAT when I say "Hello, kitty!", but he is so aware that he could spot the cat before me, so I am never sure if it is my voice and words, or the sight of the cat he is reacting to. But I am starting to think he might recognize the words!! And that new sound "kghghg", it could be a hissing, like my girls do when they play cat, or maybe he is starting to try to say kitty. All very exciting for me :)
ASL for cat pictured below, but Peter just uses his pointer finger and flicks it on his cheek.