My Baby, the singer

Kamryn can sing. No, really...she hits notes octaves higher than Mariah Carey ever could. Be jealous, MC. But seriously, Kamryn does this shrilling, and I mean shrilling, high-pitched shriek and my first thought was, wow, how on earth can she do that? and now my second thought it how in God's name do I make it stop?! Its really painful to the ear haha. And I feel bad because what if I am encouraging her to stop doing this noise and here the poor child is just trying to form the early sounds of speech. Or worse, what if she's trying to mimic me and the way I sing to her. Yikes, I hope not...plus, I can't even come close to hitting those notes. So, what is this sound? Will it stop? How can I teach her that shrieking Mariah-style is not so good when we are at the grocery store?