Kungiung, who passed away in the early 1990s, was a songman from Wadeye in the Daly region to the southwest of Darwin.

His voice and his song - "The waves are crashing on them Truwu! My dear country! Walakandha!" - reach through the decades in a recording made in 1988 at the genesis of a project to save the traditional Aboriginal performance, wangga, from extinction.

Performed by one or two men to the accompaniment of a didgeridoo and dancers with clap sticks, wangga is the subject of a new book, For the Sake of a Song: Wangga Songmen and their Repertories.

Launched on Friday night, the book and CDs are the culmination of three decades of work with indigenous composers from Arnhem Land, the Kimberley and central Australia.

Thousands of wangga songs have been documented and recorded since 1986, when Allan Marett - an emeritus professor with the University of Sydney - travelled to the Northern Territory to learn more about these dirges.

Wangga, Professor Marett explained, is a form of song and dance, received by the living in their dreams from spirits of the dead.

"Song composers are given these songs by their deceased ancestors," he said.

Performed in public, they will often form part of ceremonies held one to two years after someone has died to welcome them into the afterlife.

They are also used in circumcision rites when young boys aged 12 to 14 come of age. The idea is that the boy child "dies" and is reborn as a man, Professor Marett said.

Fewer than 20 songmen were recorded during the project and only two of those are alive today.

"These songs are dying out," Professor Marett said. Much like the languages in which they are sung.

There were once more than 250 indigenous languages across Australia. In 2005, the National Indigenous Languages Survey found just 145 were still spoken and, of those, 110 were considered "severely and critically "endangered".

"Truwu", which Kungiung performed in his native tongue, Marri Tjevin, is a mournful conversation with the spirit world and immortalises his near-extinct language.

"I would be surprised if 10 or 12 spoke the language," Professor Marret said. "It's pretty rapidly dying out."

"These smaller Daly languages are definitely on the wain."

Dr Payi Linda Ford, an honorary associate of Sydney University, belongs to the Rak Mak Mak Marranunggu clan and grew up along the Finniss River in the Daly region.

The 52-year-old speaks four indigenous languages, but said only the "old people" still spoke in the tongues of their ancestors.

"It's really, really important that we capture that now before it's gone," she said.

"I'm frightened that it's going to be lost."

For the Sake of a Song is published by Sydney University Press. It is a multimedia publication that includes a website and a series of CDs to be released later this year.