Movie subtitles

I have made a copy on both the hard drive and a dvd of The Last Samurai but find that subtitles are not diplayed when japanese is being spoken. I have copied this disc with all of the subpicture options but find that I can either have subtitles on all the time or off completely. There should only be subtitles shown when japanese is being spoken as per the original dvd. Am I doing something wrong?