Well, there's nothing much they could've done about that for the localization... That's a problem(?) with the character they made itself, since it's not like he's any better in Japanese with the lines.
As a matter of fact, so far i think he's a bit more talkative in English than I remember him being, though it could be my imagination.
http://ecx.images-amazon.com/images/I/81BbnycLqRL._AA1500_.jpg I want this. I want this so bad.
Yeah I really like Milla in this game. In the first one she sounded like she had a lisp( it was cute though. ^_^) j thought they replaced voice actor when I first heard in this game xD.
Most probably, it was because of the recording equipment problems. I saw a vid of the VA doing her voice before Xillia 1 was released. She didn't had a lisp. Even though, I didn't hear it in the first game. But just putting it out there for the ones that did. Although, I do think the voices of the original cast sound better in the sequel.