Loss of a language without documentation is considered a scientific and humanitarian catastrophe of the highest order, as important as the loss of biological species, Professor Campbell said.

"Without information on these languages, humanity loses all the knowledge that a society's language can teach us - historical information about migrations, contacts, and who they are related to. We lose their oral literature with their solutions to life's major questions and the human condition, their vocabulary with its classification of the natural universe. For example, language contains knowledge of medicinal plants of value to us all, and information about the human cognitive abilities - about our very nature - as reflected in the range of structures humans are capable of learning and using as reflected in the grammars of these languages."

Professor Campbell is currently working on the documentation of endangered languages of the Chaco, a remote region straddling the borders of Argentina, Bolivia and Paraguay. The project has funding for the next three years from the Endangered Languages Documentation Programme of the School of Oriental and African Studies at London University. Professor Campbell, along with Verónica Grondona from Argentina and Filomena Sandalo from Brazil, is trying to document Chorote, Nivaclé and Kadiwéu.

"It is a really exciting project. These are three of the least known and most endangered languages of this region with only some 500 to 100 speakers each."

Documentation means for each language a technical grammar in both English and Spanish or Portuguese, a practical grammar (for schools and non-professionals) in Spanish or Portuguese, two dictionaries for each language (a comprehensive one and a more practical one), video and audio recordings of narratives and conversations in many genres, web access for all materials produced, and preparation of teaching materials for bilingual programmes in local schools.

Professor Campbell said professional linguists felt a " moral obligation" to help document and preserve languages.

"If you don't have any documentation of the language and it becomes extinct, then no one will ever know about it - neither the community whose heritage has been lost nor the linguists who would like to know about the structure of the language for theoretical purposes."

In a separate project, Dr Ida Toivonen is documenting Inari Saami, a poorly documented language of Lapland in Finland. There are only some 300 to 400 speakers of the language remaining. Dr Toivonen is working in collaboration with Dr Diane Nelson from Leeds University, with funding from the British Academy.

Dr Toivonen and Dr Nelson have travelled to the remote area in northern Finland annually for the past six years, gathering recordings and collecting data. In April of this year, Dr Toivonen gave a language tutorial on Inari Saami at the Linguistics Association of Great Britain Conference in Sheffield. The work has significant implications for theoretical issues in linguistics.

Professor Campbell is also working with Joan Smith-Kocamahhul on a project entitled Revitalisation Strategies for Endangered Languages. The aim of the project is to compile and analyse the strategies, methods and tools used for language maintenance, stabilisation and revitalisation - strategies to protect languages from extinction - and to present a major reference work to guide future efforts in these areas. The project has been under way since 1999, supported in part by a University of Canterbury grant.

Professor Campbell has just been appointed to the Scientific Committee of the International Congress of Linguistics and will give the keynote address on historic linguistics at its meeting in Prague in July. Already this year he has lectured at the International Linguistics Institute in Rio de Janeiro, the Federal University of Rio de Janeiro and the University of Alberta. In November he will be involved with the Linguistics Graduate School Consortium of Finnish universities and in December will teach a three-week course at the Universidad del País Vasco in Spain, where he will have the opportunity to interview leaders of language revitalisation programmes for several European minority languages (Basque, Breton, and Saami) for the strategies they use for language revitalisation and maintenance.

Head of Linguistics Professor Andrew Carstairs-McCarthy said the work the department was doing in the area of endangered languages was immensely positive.

"We have a very high standing, not just in the Southern Hemisphere, but in the world which is encouraging considering our size and limited staffing."