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Explainer: what is sign language?

Sign language can be used and misused, as with any form of communication. STR/EPA

What is sign language?

Before we answer that question, it might be useful to first consider what a “language” is. Spoken languages are naturally developed complex systems that use a set of conventionalised sound-based symbols and grammatical rules. They are used to express an open-ended range of ideas, thoughts and feelings.

Any individual spoken language is shared by members of a particular speech community but may be unintelligible to members of other communities. It is passed on from one generation of speakers to the next, and inevitably changes over time. Spoken languages are used in combination with a range of vocal – changes in volume, intonation – and non-vocal elements, such as hand gestures, facial expressions and body postures.

Despite recognition since the middle of the 20th century among linguists that sign languages are also “real” languages, many misconceptions about sign languages persist. Sign languages are no different from spoken languages in any of the key features listed above, except in the channel in which the language occurs.

Signs of the times

Instead of sound-based symbols (words), sign languages use signs. Signs use a set of specific handshapes, produced in particular locations on or around the signer’s body, combined with specific movements.

In many cases, they may occur with non-manual elements, such as specific facial expressions, head movements or mouth actions. Contrasts in one of these features can make differences in meaning: compare the Australian Sign Language (Auslan) signs “sister” with “dinner”. Both use the same handshape and movement, but differ only in location of the hand on the body.

Many people are surprised to learn the “sign language” referred to in the title of this article should actually be in the plural: as is also true of spoken languages, there is no universal sign language, but rather many different sign languages around the world.

If we compare the sign meaning “sister” in Auslan, American Sign Language (ASL) and Japanese Sign Language (JSL), we see clearly that these languages differ in their vocabulary. Sign languages also differ in the details of their grammar – in Auslan, a headshake produced simultaneously with a signed sentence would negate the sentence, whereas in Greek Sign Language (GSL) a backwards head tilt might perform the same function.

Many traditions

Sign languages are an important, although often overlooked, part of Australia’s linguistic and cultural heritage.

There is an Indigenous tradition, whereby sign languages exist alongside spoken languages among the Warlpiri and Anmatyerr people of central Australia, for example. This form of signing, known as an “alternate” sign language, is used primarily by hearing people as an alternative to speech in certain situations (although deaf people in these communities may also use these sign languages).

There is also the European deaf sign language tradition in Australia, with British Sign Language (BSL) and Irish Sign Language (ISL) having been brought to this country by deaf convicts and immigrants from the early 19th century onwards.

BSL and ISL are both distinct sign languages that developed independently in their respective countries. Modern Auslan has incorporated some ISL signs, but it most closely resembles BSL (as does New Zealand Sign Language – NZSL). All of these sign languages are distinct from ASL, despite the fact that they are all used in English-speaking countries.

There are also regional differences within sign languages, so “car” has one form in Victoria and another in the rest of the country. Fluent signers understand both, just as English speakers know the words “automobile” and “car” refer to the same thing.


The reason for this surprising sign language diversity reflects the fact that, unlike what is often assumed, sign languages were not invented by any one individual.

Although Abbé de L’Epée, the priest who founded the world’s first public school for deaf children in Paris in 1760, is often mistakenly credited with creating sign language to instruct his students, he is known to have first learned to sign from deaf adults.

There was already an active signing deaf community in Paris at the time, most of whom had no formal education. As with other sign languages, French Sign Language (LSF) developed spontaneously when deaf people came together to form a community.

Scott Ableman

This process has been repeated many times throughout history in different parts of the world, creating the modern diversity in sign languages. Recently a new sign language emerged in Nicaragua, as a direct result of bringing deaf children together in the first time in a newly created school for the deaf in the 1980s.

Because sign languages develop independently within deaf communities, they are not manual codes for spoken languages – they have their own vocabulary and grammar. This means there is often not a word for sign equivalence between Auslan and English.

A single sign in Auslan can mean “I’m glad that’s over!” or “none of your business!”. There is one sign meaning “light” as in “not heavy”, and another meaning “light” as in “not dark”, just as there are different words for these concepts in different spoken languages. The grammar of Auslan is also different, with a more flexible order of elements than English.

The signed phrase “cake finish eat you” can, with the right combination of facial expression with the signs, mean: “Have you eaten the cake?”

A unique feature of sign language grammar is their use of space to show who is doing what to whom. The Auslan sign meaning “help” can move from signer to addressee to mean “I help you” or reverse its movement to mean “you help me”.

A few signs in Auslan are similar to gestures used by hearing people in Australian culture, such as “drink” and “think”. But the relationship between the meaning and form of many other signs only makes sense when you have learned the connection, such as “Sydney” and “forget”.

And many others signs are forms that hearing people would never recognise, such as signs meaning “beach” and “Melbourne”. This demonstrates sign languages are not simply combinations of mime and gesture – the vocabulary and grammar have to be learned, as is the case with any other language.


Sign languages have the same capacity to express subtle, technical and complex meanings as spoken languages do. There are Auslan signs meaning “discrimination”, “diagnosis” and “philosophy”, for example.

The fingerspelling alphabet means any English word (or from any language with a Roman script) can be introduced into the language. There are established traditions in many parts of the world of sign language jokes (see above) and comedy, sign singing, poetry, theatre, and story-telling.


Research from the study of sign language acquisition suggests that children from signing families make similar kinds of errors and move through the same stages of language development at roughly the same ages as children learning spoken languages.

Recent neuroscience research also shows that the same areas in the left hemisphere of the brain are crucial for the production and comprehension of both signed and spoken languages, suggesting that – for the brain – language is language, regardless of whether it is visual-gestural or auditory-oral.

Most importantly, there seems to be no evidence to support assumptions made by some in the deafness sector that the use of sign language alongside speech in deaf children with cochlear implants leads to poorer spoken language outcomes.

In fact, there is good reason to believe that deaf children can only benefit from bilingual education in sign and spoken languages. Indeed, the linguistic human rights of deaf communities are enshrined in the United Nations Convention on the Rights of People with Disabilities.

Australia is a signatory to this treaty, which states that governments have an obligation to support and promote the linguistic rights of signing deaf communities. Together with Deaf Australia and the World Federation of the Deaf, I hope that increased understanding will lead to a greater recognition of the irreplaceable role played by sign languages as the primary languages of deaf communities around the world.

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