The deaf have fought to preserve sign language in the past. Fifty deaf students protested a ban on sign language with a strike in 1973 at the Hong Kong School for the Deaf, the first such school in Hong Kong, established in 1935. The students boycotted classes, but to no avail.
The second such school was set up in 1948 by a deaf couple from Shanghai, and introduced Shanghainese-style sign language to Hong Kong. The school closed in 1976. In 2004, the Hong Kong School for the Deaf became a school for able-bodied children, and was renamed Chun Tok School.
Chan Yi-hin, author of My Deaf Friends, says it originates from two streams. "One is the Shanghai stream. Another was developed by deaf students in secret in schools that ban the use of sign language. That's why there are no uniform expressions in Hong Kong sign language, with several signs for words like 'Tuen Mun', 'Kwun Tong' and 'green'."
Gladys Tang Wai-lan, director of Chinese University's Centre for Sign Linguistics and Deaf Studies, says there's no need for a uniform standard. "Cantonese also has different expressions. Once you look for a uniform standard, you need to categorise some expressions as right and others as wrong."
But both the centre and the Lutheran School for the Deaf - the only such school in the city today - are developing databases of sign language for better reference for the deaf. Chinese University's centre recently received funding of HK$216,000 from the Labour and Welfare Bureau to develop an online sign language database. It has compiled more than 1,100 signs.
The Lutheran School for the Deaf received almost HK$3 million in funding from the Quality Education Fund last year to start a three-year project to develop an online video sign-language dictionary aimed at the senior secondary students.
The school's principal, Ng Yuk-chun, says the lack of uniform expressions could hinder academic studies."Different teachers have different signs for specific words. The video dictionary will have 6,000 words in common usage in the curriculum. It will be ready for use in 2015. Students and teachers can look up specific words and terms, like 'liberal studies' and 'domino effect'."
Video: Sign language interpreter for the hearing impaired