[marty]

I know nothing about proper singing techniques, but for me it's very obvious it was just a natural change due to her growing up. And maybe a little bit the result of her constant singing training in the meanwhile. I really find her early way of singing adorable and charming, and I think she had more power in her voice at that time too. But it's kind of normal, she just has started. Even Mariah Carey can't really sing the same way as before right now, it's bound to happen if one keeps on singing day after day.
I love her current way of singing, and I find her discography very interesting because of this gradual changing on her voice as well. I mean, it's so fascinating when you listen to her albums one after another, and can actually pinpoint her vocal evolution! Isn't it more interesting than a voice that's always the same through the years?