The Power of Z!
The games have that issue too. Unless you're specifically looking at English Translation Lillie's dialogue with the knowledge that she doesn't talk the same way most other characters do, it's nearly impossible to notice.
It's a fairly big part of her character that should have been handled much better.
I completely agree; it's a fairly big part of Lilie's character that should have been handled much better. Lilie's way of speaking is just so different from the other characters' that to hear her imitate Satoshi (whose way of speaking is pretty much the complete opposite of hers) is both funny and cute, because it sounds so odd coming from her. English Lillie's delivery of that line just sounded...off. Also, I think some of the humor of that line was lost, since Lillie said, "Very awesome," rather than just "Awesome," which is what Ash had originally said.
(I probably am looking at English dub Lillie's dialogue with the knowledge that she doesn't speak the same way most other characters do. At least in the games, the problem probably isn't exacerbated by the voice acting, since, well, there is no voice acting. ^_^; )