Sign language interpreting allows Deaf people to access spoken language media in their own language. Sign languages, such as Spanish Sign Language, British Sign Language or American Sign Language, are fully-fledged languages and unrelated to the spoken majority language in their country, so for Deaf signers the spoken majority language effectively is a foreign language. In addition, literacy levels in Deaf communities tend to be relatively low. Research shows that as a result Deaf people who cannot rely on their hearing often also struggle to follow subtitles.
Through a sign language interpreter, information is presented in the visual mode and the first language of Deaf people by a professional who is also familiar with their culture and communication needs. In the media context, sign language interpreting is increasingly provided by Deaf translator/interpreters who interpret written text from an autocue. Giving sign language interpreters access to the script and additional information, in particular related to visuals, well in advance helps to ensure a clear and fully accessible interpretation. The way the interpreter is presented on screen also deserves careful consideration as this too influences how well their interpretation is understood by viewers.
References:
Stone, Christopher (2007) Deaf access for Deaf people: the translation of the television news from English into British Sign Language, in J. Díaz Cintas, P. Orero & A. Remael (eds.) Media for All: Subtitling for the Deaf, Audio Description, and Sign Language, Amsterdam: Rodopi, p. 71-88.