So-called ‘village’ sign languages have been widely reported in the scientific literature (not to mention the mass media) (Grace, 1985; Kisch, 2004, 2008). These are (or were) found in a number of communities scattered around the world where the sign language of the deaf is also routinely used by hearing individuals. Such communities are, without exception, culturally or geographically isolated (often practising endogamy) and have a high proportion of profoundly deaf members. The deaf group develops its own sign language and the hearing members acquire mastery of it to varying degrees, using it in particular to communicate with deaf friends and relatives.

Australia appears to be unique, however, in that almost every indigenous community may have had an alternate sign language. This was understood by all the population and used by the majority – a situation which is maintained in some communities to this day. This population, while living in relatively self-contained groups for most of the year, has strong cultural connections over large areas and largely exogamous marriage practices. Factors commonly cited as contributing to the development and maintenance of these systems are both cultural (including ceremonial speech taboos – especially by women in mourning and by young males undergoing initiation – and avoidance behaviour within certain kinship relations) and practical (communicating over distance, while hunting, or with others – the profoundly deaf or the monolingual outsider – who cannot understand spoken language).

But Kendon (1988) points out “some use of signing has been recorded from many parts of Australia, including areas where extended speech taboos have not been reported” and Kwek (1991) writes “In this particular case [Punmu, Western Australia], it is hard to imagine a set of circumstances that would proscribe normal speech use to the extent of leading to the development of what appears to be a relatively complex sign system.”

The proportion of the indigenous population with severe to profound deafness is somewhat higher than in the mainstream population, but a much higher proportion has a mild-to-moderate conductive hearing loss. In Australia the prevalence of severe hearing loss (60-90 dB) in males aged 15-50 in the general population is around 1.0%, whilst the prevalence of mild-to-moderate loss (20-60 dB) is around 6.7% (Access Economics, 2006). A recent study of 134 Northern Territory (NT) Aboriginal prison inmates (Vanderpoll & Howard, 2012) found that 9.7% of that population had a severe hearing loss (65-90 dB), whereas 85% had a mild-to-moderate loss (25-65 dB). This widespread hearing loss has been largely ignored as a potential factor in the development of Australian indigenous signing