Why did Seagal need a japanese dialogue teacher?

[Charles Bronson]

At the end credits of his recent movie "Into the Sun" there was listed a guy as Steven Seagal´s japanese dialogue teacher.
I don´t understand that. I always thought he speaks perfectly japanese.
What does that mean-dialogue teacher?

 

[suziwong]

At the end credits of his recent movie "Into the Sun" there was listed a guy as Steven Seagal´s japanese dialogue teacher.
I don´t understand that. I always thought he speaks perfectly japanese.
What does that mean-dialogue teacher?

Dear Mr. Bronson,

Actually we don't know why but may be for dialect. Because we know he speaks Japanese fluently.
suzi