New Zealand Sign Language or NZSL () is the main language of the deaf community in New Zealand. It became an official language of New Zealand in April 2006 under the New Zealand Sign Language Act 2006. The purpose of the act was to create rights and obligations in the use of NZSL throughout the legal system and to ensure that the Deaf community had the same access to government information and services as everybody else. According to the 2013 Census, over 20,000 New Zealanders know NZSL. New Zealand Sign Language has its roots in British Sign Language (BSL), and may be technically considered a dialect of British, Australian and New Zealand Sign Language (BANZSL). There are 62.5% similarities found in British Sign Language and NZSL, compared with 33% of NZSL signs found in American Sign Language. Like other natural sign languages, it was devised by and for deaf people, with no linguistic connection to a spoken or written language. NZSL uses the same two-handed manual alphabet as BSL (British Sign Language) and Auslan (Australian Sign Language). It uses more lip-patterns in conjunction with hand and facial movement to cue signs than BSL, reflecting New Zealand's history of oralist education of deaf people. Its vocabulary includes Māori concepts such as marae and tangi, and signs for New Zealand placenames (e.g., Rotorua – mudpools, and Christchurch – 2 Cs, represents ChCh.) History The early British immigrants to New Zealand who were deaf brought British Sign Language with them. The first known teacher of sign language was Dorcas Mitchell, who taught the children of one family in Charteris Bay, Lyttelton Harbour, from 1868 to 1877. By 1877 she had taught 42 pupils. When the first school for the deaf (then called the Sumner Deaf and Dumb Institution) was opened at Sumner, south east of Christchurch in 1878, Mitchell applied unsuccessfully for the position of principal. Instead it went to Gerrit Van Asch, who agreed with the Milan congress of deaf educators of 1880 (to which no deaf people were invited) that teaching should be oral only, and that sign language should be forbidden. (He would not even admit pupils who could sign, so only 14 were admitted.) This was the policy of the school until 1979. A documentary film about the school made in the 1950s makes no mention of sign language. Similar policies were maintained at the schools at Titirangi and