Unserdeutsch (Rabaul Creole German) is a dying language. In this respect, it's not unique—languages around the world are dying. See, for example, http://www.endangered-languages.com/. By the end of this century, I would be very pleasantly surprised if half of the languages spoken today still have native speakers.
We use a language because it has a purpose. Among the purposes are:
- to communicate within our group, be it the family or the ethnic group
- to communicate with others outside our group (many people learn English for this reason)
- to access formal or informal education (many people used to learn Latin for this purpose)
- to revere the Divine (many Hindus learn Sanskrit for this reason)
When these purposes no longer exist, people stop learning or using the language, even if it is their native tongue.
In the case of Unserdeutsch, the small community of speakers was always at least trilingual in Tok Pisin (New Guinea Pidgin English) for communication with others, as well as English and/or German for communication with others, education, and religious worship. The only real purpose of Unserdeutsch was for communication within their group and as a badge of ethnic identity.
When the colour bar was lowered in the 1960s, and mixed-race persons could take Ausralian citizenship and move to Australia, most families sent their children to school in Australia. At Independence, most made plans to move permanently to Australia, where they saw their future as being more secure. Many, perhaps, most, young people from the 1960s on married outside their small community, so that their children did not identify primarily as mixed-race Germans and did not learn to speak Unserdeutsch.
Because the language no longer has a purpose, younger members of the community, now dispersed along the Australian eastern seaboard, grow up with English as their dominant language. while they may know some phrases from a grandparent, they are not fluent speakers of the language. The youngest fluent speakers of the language are now in their sixties. The language is therefore unlikely to survive as the language of native speakers for more than a few decades. The challenge to linguists and members of the community now is to document the language so that future generations will have access to this unique language whose birth and death symbolise the turmoil of European colonialism and the emergence of the modern nation-state of Papua New Guinea.