Marie Smith knows that her language - the Alaskan tongue of Eyak - will die with her. And she mourns its passing.

"If you were expecting a little baby, and it went back to its home so that it wasn't born alive, how would you feel?" says Smith, 85, who moved to Anchorage from her tribal home on Prince William Sound in 1973.

A fisherman's daughter, Smith grew up with Eyak, a branch of the Athabaskan-Tlingit family of languages spoken for 3,000 years in Cordova, along the Copper River. But she stopped speaking Eyak when she attended government schools. Neither her children nor grandchildren know the language.

"I should have made them learn it, but they just weren't interested," she said.

Eyak is among thousands of languages expected to disappear in the next 100 years, a mortality rate that has linguists rushing to document and save the world's endangered tongues. "We're losing a part of our cultural history," said Michael Krauss, a University of Alaska linguistics professor and founder of the Alaska Native Language Center, established in the 1970s to save the state's 20 native tongues.

Krauss and other linguists blame the losses on economic and social trends, politics, improved transportation and the global reach of telecommunications. Whatever the reason, they predict that up to half of the world's 6,800 tongues could die over the next century - and hundreds more will disappear in the century after that.

"I'd be the happiest guy in the world if I were wrong," Krauss said. But he noted that only 500 to 600 languages are spoken by at least two generations, making them relatively safe from extinction.

According to experts, half the people on the planet use just 15 languages to communicate, while 10 percent of the population speak in one of about 6,800 distinct tongues. Half the world's languages are spoken by fewer than 2,500 people, mostly in remote areas that are becoming less remote every day.

Global economics are prompting the young to leave isolated villages in India, Mexico and South America. They're headed for cities in search of better lives, leaving native tongues behind. Meanwhile, satellite TV and the Internet are reaching into isolated areas of Papua New Guinea, a South Pacific island nation with 832 languages, more than any other country.

"If you go to Papua New Guinea and go out in the most remote areas you can find and you'll see grass huts, and alongside one of them you'll see a satellite dish, and of course the TV that's coming in is coming in English," said Anthony Aristar, a linguistics professor at Wayne State University in Detroit who studies dying languages. He is creating a $2 million database listing the world's tongues.

Words come, languages go

The death of a language is nothing new. The spoken word, developed tens of thousands of years ago, is in constant motion. Inventions inspire word creation, wars transform nations, poverty prompts waves of immigration, and other historic events - such as the opening of the American West to European settlers - create conditions where one tongue comes to dominate others.

For example, linguists note that the Norman Conquest transformed early English, which has its roots in German. Latin, the language of the Roman Empire, replaced Etruscan and Punic before it diversified and influenced 30 other languages, including English.

Sometimes, government policies kill a language. Many Native American languages are near extinction - the Lipon Apache have two or three speakers left - in part because government-run boarding schools punished students for speaking native languages until the 1960s.

Krauss says that about half of the 200 languages native to North America will probably die out over the next century because so few children are picking up them up.

Alan Caldwell, director of the Culture Center at the College of the Menominee Nation in Wisconsin, remembers his father telling of having his hand slapped with a ruler and his mouth washed out with soap for speaking Menominee at the reservation school, which has closed. The experience left the elder Caldwell, who died in 1972, reluctant to speak the native tongue, or pass it on.

"We'd be at the dinner table and we would ask him, 'How do you count to 10? How do you say salt and pepper?' And depending on his mood, most often his response was, 'You don't have a need to know that, it won't do you any good,'" Caldwell said.

As a result, only 40 of the tribe's 8,800 members speak the original language. That's one reason why Monica McCauley, a University of Wisconsin researcher, drives three hours to the reservation each week.

Macaulay recently won a National Science Foundation grant to compile the first complete Menominee dictionary. The project includes taping the tribe's elders and transcribing conversations to capture the nuances of the language.