In Canberra on a speaking tour of Australia, Wade Davis noted that of the 7000 languages spoken today, half were not being taught to children. Of the 670 indigenous languages and dialects spoken in Australia in 1788, less than 20 were still in daily use.

''There is kind of a haunting consensus, right across the linguistic academic community,'' Dr Davis said yesterday of the language loss.

With a PhD in ethnobotany from Harvard University, Dr Davis has worked in Peru, Tibet, Mali, Greenland and Australia. He has also explored plants in the Amazon and the Andes and researched how zombies are created in Haiti.

''Language of course is not just grammar and vocabulary, but it's sort of a flash of the human spirit. It's a vehicle through which the soul of each culture comes into the world. It's like an old-growth forest of the mind,'' he said.

Despite the rate of language loss, the Canadian-born Dr Davis said he was optimistic about the future.

''If human beings are the agents of cultural destruction we can be the facilitators of cultural survival,'' he said. ''That doesn't mean every language is going to survive ... but even the act of documenting grammar and dictionaries from those languages ... becomes a tremendous kernel of rebirth and hope.''

Dr Davis warned against Western nations' tendency to see their culture as ''the paragon of human potential''. He said genetic research over the past 20 years has proven that all humans had been ''cut from the same genetic cloth''.

''Other people in the world aren't failed attempts at being us, failed attempts at being modern,'' he said. ''They're unique answers to a fundamental question, 'What does it mean to be human and alive?'''

Again, Dr Davis was optimistic about humans' capacity to balance traditional and modern cultural outlooks, particularly in Australia, Canada and Colombia.

''Forty years ago, first nations of land were treated with contempt, frankly. But all those countries have recognised that the existence of multicultural and the existence of traditional ethnicities do not embarrass the nation state, they enrich it.'' he said.