Subtitling is similar to closed caption with a few exception. Subtitling like closed captioning is turned on or off by the comsumer watching the program typically on a DVD or Bluray. Unlike closed caption subtitling does not add sound effects and noises heard in the audio, but rather concentrates on verbal audio only. Sometimes subtitles are added into a television program is the person on the screen is speaking in another language than the program is based in. An example of this would be that you have an English program and there is someone in the program that is speaking in Spanish. The subtitles are added in this case so that your English viewers know what is being said by the Spanish speaker.