Because I bought it in Japan.

3 seconds sound clip from the Batman (1989) movie soundboard.

You can hear this line at 00:21:05 in the Blu-ray version of the movie.

Quote context

[...]

- Check this out. He must have been king of the wicker people.

- Where did this come from?

- I have no idea.

- It's Japanese.

- How do you know?

- Because I bought it in Japan.

- Who are you?

- Oh, sorry. Bruce Wayne.

- Alexander Knox.

- Hi.

[...]