It's difficult to explain technically, but here it goes: film is projected at 24 frames per second in the NTSC projection system that's utilized in North America, parts of South America, and Japan; in the PAL system that's utilized in the rest of the world - particularly Europe and Australia, film is projected at 25 fps instead of 24, so because the film is projected at a higher framerate in PAL, there's a 4% increase in speed, which is why PAL versions of movies and shows sound sped-up.