I would bet that the japanese releses are not 
subtitled in english. Although I don't know for 
sure.
   In my experience japanese releases are not 
available in english for the purpose of keeping 
down pirating. Mononoke was going to be released on 
DVD in America without any additional language 
tracks because it isn't available yet in Japan. The 
companies feared bootleg copies would end up in 
Japan. Due to an outcry from fans the DVD release 
is now in limbo.