"'Batman' took 10 months to film, and by the time I stopped working on it, it took a long time before my English accent came out again. I was actually having to try for it"

Christian Bale's quote is a testimony to the commitment he took into his role as Batman in the film of the same name. He invested 10 months recording the flick, and also by the time he finished, his English accent had actually been replaced by the American accent he made use of for the role. This shows how a lot he immersed himself in the character, as well as how much effort he took into perfecting the duty. He needed to proactively try to bring back his English accent after the recording was done, which speaks to the degree of dedication he had to the role. It's clear that Christian Bale placed a great deal of effort and time right into his portrayal of Batman, and also his quote is a testimony to that.