Is the sound in the movie recorded on film? In what form was it recorded?

When shooting a movie, images and sounds are recorded separately. Images are recorded on film, and sounds are recorded on tape. Later, the sound recorded on the tape was "optically converted" into a sound film, which was called a negative film. Then the sound correction is reversed, and then the sound is copied to the projection copy and attached to one side of the film in the form of optical vocal cords. (Only one side is vocal cords) When showing, the optical vocal cords are replaced by electric models.