Language Matters | Why there is no universal sign language, and how the embrace of non-verbal communication is a welcome sign of the times

September 23 is the International Day of Sign Languages, but most of us know little about the means of non-verbal communi­cation that has proven invaluable for the deaf and hard of hearing around the world. Perhaps surprisingly, there is not just one sign language, and different countries have different systems, often with regional variants. Like spoken languages, they developed among groups of people interacting with each other.

Many of the world’s major sign languages (exceptions include Chinese, Japanese, Indo-Pakistani and Levantine Arabic) can be traced to two origins. British Sign Language (BSL) spread to the Commonwealth with 19th-century British settlers; a sign language within England’s deaf communities was noted from 1570. BSL, New Zealand Sign Language (NZSL) and Australian Sign Language (Auslan) share many similarities and comprise the BANZSL language family.

French Sign Language, meanwhile, established in the late 1700s, is usually identified as the root of American Sign Language (ASL), which developed in the 19th century, and of Quebec and many European sign languages. In the 1970s, with contact between deaf users of different sign languages, a pidgin – International Sign – was developed.

Sign languages evolve within deaf communities and neither mirror nor are dependent on the surrounding spoken lang­uages; they are fully fledged natural languages with intricate grammatical organisation of their own. Auslan word order is different from English; and ASL and BSL differ significantly, more so than American and British English.

While sign languages are usually associated with hand shapes, the rules for well-formed sentences also include eyebrow position, eye position, hand motions and where signs occur in relation to the body. Facial expressions also play a fundamental role, notating rhythm and tone.