Very few technologies are as widespread as television. Almost every household in the UK has a television set and it is a primary source of information and entertainment. We know that having access to television programmes is now considered necessary to participate as an equal citizen, and this includes British Sign Language (BSL) users.

The language challenge

BSL is the first or preferred language of over 50,000 people, and is syntactically and grammatically very different to English. Many deaf people have great difficulty picking up a spoken language without understanding the sounds that are being made, so they have evolved a language of their own that uses media they understand better: vision and movement.

Many hearing people think that with the presence of subtitles there is little need for sign language on television, without realising that sign language users are in fact being asked to access programmes in their second language. So signing on television lets them access programmes in the same way as everyone else. There are other advantages of having signing on television. Over 100,000 people have passed a Level 1 BSL course, and the number of BSL users is growing with a large demand for new courses. Signing on television can help anyone who is learning BSL.

Open or closed signing?

On traditional, analogue television, some programmes are repeated with in-vision signing - with the signer visible on one side of the screen - usually outside mainstream viewing hours. This is called open signing. With the advent of digital television, the idea of closed signing (where you can switch it on or off as you like, much like switching subtitles on or off) is becoming more feasible.

Open signing

Open signing works by having a a signer translating in-vision for a particular programme. The advantage of this method is that no new technology or extra bandwidth is required, as the signer is part of the main image. Across Europe open signing has been available for some time but, as with open subtitling, the wider audience tends to find it intrusive. As a result, open signed programmes are usually limited in quantity and are broadcast as repeats at unsocial times of the night.

Clearly it is possible to provide a dedicated digital or analogue channel for deaf people who need to use sign language, but it would need considerable support. In addition, this approach would separate sign language users from mainstream audiences, rather than integrating them.

Closed signing

A far better way to increase the amount of signed programmes is to develop technology for closed signing. Just as with closed subtitles, viewers could simply switch the signing on or off by pressing a button on their remote control.

Broadcasters could deliver this by making a parallel stream of signing available for the main programme. When switched on, this secondary picture would be shown together with the main broadcast. However, this means that more bandwidth is needed, and that is a very scarce resource. To make it practically and economically viable, the signing stream has to be as small in size as possible.

Obviously, television sets and other equipment would need to have functions built in to recognise and display the signing. And agreements would need to be made between broadcasters to provide such secondary streams in a standard format.

Together with the BBC's Research and Development group, RNID is working on technologies to make closed signing a reality. As part of that work, our New Technologies team has carried out extensive research into the user requirements and watching habits of deaf people who watch television with in-vision sign language interpretation.

Use of avatars

One way of dramatically reducing the bandwidth requirements for closed signing is to use virtual humans (computer generated animations known as avatars) that are built into television sets and settop boxes. RNID has been involved in various projects and research in this field. Again in collaboration with the BBC, we are exploring various means of using avatars for closed signing.

In addition to the bandwidth problems, avatars help in addressing the shortage of human interpreters. As such, they are not intended to replace human interpreters, but rather to increase the amount of signed content available to sign language users.

Further information

You can find out more by contacting us by email at ict@rnid.org.uk.