Riding the crest of globalization and technology, English dominates the world as no language ever has, and some linguists are now saying it may never be dethroned as the king of languages.
Others see pitfalls, but the factors they cite only underscore the grip English has on the world: cataclysms like nuclear war or climate change or the eventual perfection of a translation machine that would make a common language unnecessary.
Some insist that linguistic evolution will continue to take its course over the centuries and that English could eventually die as a common language as Latin did, or Phoenician or Sanskrit or Sogdian before it.
"If you stay in the mind-set of 15th-century Europe, the future of Latin is extremely bright," said Nicholas Ostler, the author of a language history called "Empires of the Word" who is writing a history of Latin. "If you stay in the mind-set of the 20th-century world, the future of English is extremely bright."
That skepticism seems to be a minority view. Experts on the English language like David Crystal, author of "English as a Global Language," say the world has changed so drastically that history is no longer a guide.
"This is the first time we actually have a language spoken genuinely globally by every country in the world," he said. "There are no precedents to help us see what will happen."
John McWhorter, a linguist at the Manhattan Institute, a research group in New York, and the author of a history of language called "The Power of Babel," was more unequivocal.
"English is dominant in a way that no language has ever been before," he said. "It is vastly unclear to me what actual mechanism could uproot English given conditions as they are."
As a new millennium begins, scholars say that about one-fourth of the world's population can communicate to some degree in English.
It is the common language in almost every endeavor, from science to air traffic control to the global jihad, where it is apparently the means of communication between speakers of Arabic and other languages.
It has consolidated its dominance as the language of the Internet, where 80 percent of the world's electronically stored information is in English, according to David Graddol, a linguist and researcher.
There may be more native speakers of Chinese, Spanish or Hindi, but it is English they speak when they talk across cultures, and English they teach their children to help them become citizens of an increasingly intertwined world.
At telephone call centers around the world, the emblem of a globalized workplace, the language spoken is, naturally, English. On the radio, pop music carries the sounds of English to almost every corner of the earth.
"English has become the second language of everybody," said Mark Warschauer, a professor of education and informatics at the University of California, Irvine. "It's gotten to the point where almost in any part of the world to be educated means to know English."
In some places, he said, English has invaded the workplace along with the global economy. Some Swedish companies, for example, use English within the workplace, even though they are in Sweden, because so much of their business is done, through the Internet and other communcations, with the outside world.
As English continues to spread, the linguists say, it is fragmenting, as Latin did, into a family of dialects - and perhaps eventually fully fledged languages - known as Englishes.
New vernaculars have emerged in such places as Singapore, Nigeria and the Caribbean, although widespread literacy and mass communication may be slowing the natural process of diversification.
The pidgin of Papua New Guinea already has its own literature and translations of Shakespeare. One enterprising scholar has translated "Don Quixote" into Spanglish, the hybrid of English and Spanish that is spoken along the borders of Mexico and the United States.
But unlike Latin and other former common languages, most scholars say English seems to be too widespread and too deeply entrenched to die out. Instead, it is likely to survive in some simplified international form - sometimes called Globish or World Standard Spoken English - side by side with its offspring.
"You have too many words in English," said Jean-Paul Nerrière, a retired vice president of IBM USA, who is French. He has proposed his own version of Globish that would have just 15,000 simple words for use by nonnative speakers.
"We are a majority," Nerrière said, "so our way of speaking English should be the official way of speaking English."
As a simplified form of global English emerges, the diverging forms spoken in Britain and America could become no more than local dialects - two more Englishes alongside the Singlish spoken in Singapore or the Taglish spoken in the Philippines. A native speaker of English might need to become bilingual in his own language to converse with other speakers of global English.
"We may well be approaching a critical moment in human linguistic history," Crystal wrote. "It is possible that a global language will emerge only once."
After that, Crystal said, it would be very hard to dislodge. "The last quarter of the 20th century will be seen as a critical time in the emergence of this global language," he said.
English and globalization have spread hand in hand through the world, Warschauer said. "Having a global language has assisted globalization, and globalization has consolidated the global language," he said. That process started with the dominance of two successive English-speaking empires, British and American, and continues today with the new virtual empire of the Internet.
Although Chinese and other languages are rapidly increasing their share of Internet traffic, English is likely to remain the common language, experts say.
"Estonian has an amazing Web presence," McWhorter said. But when Estonians speak on the Internet with people outside their small country, they will continue to use English.
In a phenomenon never seen before, Crystal said, English is spoken in some form by three times as many nonnative speakers as native speakers.
The teaching of English has become a multibillion-dollar industry, and according to Graddol, nearly one-third of the world's population will soon be studying English.
By the most common estimates, 400 million people speak English as a first language, another 300 million to 500 million as a fluent second language, and perhaps 750 million as a foreign language.
The largest English-speaking nation in the world, the United States, has only about 20 percent of the world's English speakers. In Asia alone, an estimated 350 million people speak English, about the same as the combined English-speaking populations of Britain, the United States and Canada.
Thus the English language no longer "belongs" to its native speakers but to the world, just as organized soccer, say, is an international sport that is no longer associated with its origins in Britain.
Two years ago for the first time, a nonnative English speaker, Jun Liu of China, was elected president of the global education association Teachers of English to Speakers of Other Languages, known as Tesol.
Even if English were somehow to collapse as the language of its birthplace, England, Crystal said, it would continue its worldwide dominance unperturbed.
A recent study found that the Queen's English - the language as spoken by the queen of England - has evolved over the past 50 years, becoming slightly less plummy and slightly more proletarian. But the future evolution of the language, scholars say, is more likely to belong to the broken-English speakers of far-off lands.
"The people who were once colonized by the language are now rapidly remaking it, domesticating it, becoming more and more relaxed about the way they use it," wrote the Indian author Salman Rushdie in an essay in 1991.
But in the end, Ostler said, all of this could become moot. The advance of technology that helped push English into its commanding position could pull it down again.
Though it still sounds like science fiction, it seems likely that some time, many decades from now, a machine will be perfected that can produce Urdu when it hears someone speaking German.
"With progress, the problem of machine translation and automatic interpreting is going to be solved," Ostler said, "and the need for a common language is going to be technically replaced."
Tomorrow: The world's top universities are shifting into English, but the move is not without its difficulties, for faculty and students.