Microsoft has released an update giving Windows an interface in the Quechua language, descended from the tongue of South America's ancient Incas.

The new interface is the fruit of a deal with the Peruvian government, which ordered 5,000 Quechua-language Windows systems and co-ordinated the translation with Microsoft and academics from three Peruvian universities. Last week Microsoft made the interface available to the public for the first time, in a launch event in Sucre, Bolivia.

Since taking power in January, Bolivian president Evo Morales - himself an Aymara Indian - has been promoting the indigenous cultures of South America's poorest country. Two and a half million people speak Quechua in Bolivia, and there are a total of 10 million Quechua speakers across South America.

The update, available for Spanish-language editions of Windows XP and Office 2003, uses words such as "kichay" for "open" and "waqaychay" for "save". "File" is translated as "kipu", literally referring to an ancient Incan system of recording information using knotted strings. "Internet" is "llika", Quechua for spider web.

Microsoft said its efforts were designed to make Windows more accessible. "Technology should be available to all," the company said in a statement. "It helps improve the lives of people."

In the past couple of years Microsoft has upped its efforts to create local language versions of Windows, in the face of competition from Linux, which can be freely modified and localised, and doesn't carry licensing fees.

In the past, however, most of the attention has been focussed on localised versions of Windows XP "Starter Edition", a stripped-down version sold for a lower cost than standard Windows. Versions of so-called Windows XP Lite have appeared in the Indian subcontinent, Brazil, Russia, the Phillipines, Thailand, Malaysia and Indonesia.

Bolivia's foreign minister, David Choquehuanca, confirmed that Quechua Windows will cost more than most Quechua speakers can afford, since it only works with ordinary licensed copies of Windows XP. "We congratulate Microsoft for having facilitated the use of computers in our own languages, but we have to advance toward systems that are more open because we still have to pay a license fee (to use the software) to Microsoft," he told Reuters.

There are a few gaps in the localisation programme, as one invited Quechua speaker found when she typed a letter at last week's preview; Word's automatic spell checker underlined every word in red.

The language interface pack is available for download from Microsoft's website.