<P> Auslan, BSL and NZSL have 82% of signs identical (using concepts from a Swadesh list). When considering similar or related signs as well as identical, they are 98% cognate . Further information will be available after the completion of the BSL corpus is completed and allows for comparison with the Auslan corpus and the Sociolinguistic Variation in New Zealand Sign Language project . There continues to be language contact between BSL, Auslan and NZSL through migration (deaf people and interpreters), the media (television programmes such as See Hear, Switch, Rush and SignPost are often recorded and shared informally in all three countries) and conferences (the World Federation of the Deaf Conference--WFD--in Brisbane 1999 saw many British deaf people travelling to Australia). </P> <P> Makaton, a communication system for people with cognitive impairments or other communication difficulties, was originally developed with signs borrowed from British Sign Language . The sign language used in Sri Lanka is also closely related to BSL despite the oral language not being English, demonstrating the distance between sign languages and spoken ones . </P> <P> BSL users campaigned to have BSL recognised on an official level . BSL was recognised as a language in its own right by the UK government on 18 March 2003, but it has no legal protection . There is, however, legislation requiring the provision of interpreters such as the Police and Criminal Evidence Act 1984 . </P> <P> BSL has many regional dialects . Signs used in Scotland, for example, may not be used, and may not be understood immediately by those in Southern England, and vice versa . Some signs are even more local, occurring only in certain towns or cities (such as the Manchester system of number signs). Likewise, some may go in or out of fashion, or evolve over time, just as terms in oral languages do . Families may have signs unique to them to accommodate for certain situations or to describe an object that may otherwise require fingerspelling . </P>

When was bsl recognised as an official language