English, we would like to think, is the Latin of the 21st century. Just as that provincial Italian mumble came to drown out the established tongues of the ancient world – Egyptian, Persian, Aramaic, Greek – so English, originally the jargon of a few Germanic marauders, has become the tool with which the world is governed.

Because it is the first language of the world’s greatest power, it is a second language everywhere: English can’t boast as many speakers as Mandarin or Hindi, but the Chinese and the Indians are eager to learn it. Shakespeare seemed to have intuited this imperial fate in “Julius Caesar,” where his prophecy applies equally to Brutus’s Latin and his own English: “How many ages hence / Shall this our lofty scene be acted o’er, / In states unborn, and accents yet unknown!”

If this resemblance is a source of pride, however, it also raises an obvious fear: If Latin could die, so could English. The death of languages, even the most prestigious and powerful, is the mesmerizing subject at the heart of Nicholas Ostler’s “Empires of the Word” (HarperCollins, 615 pages, $29.95). Latin started to split into mutually unintelligible dialects almost 1,500 years ago; it lived on in scholarly cold storage until the 18th century, but today even educated people don’t feel any need to learn it. Other languages met with still more dire and dramatic ends.

Today, Greek is spoken only on the southern rim of the Balkan peninsula; at its height, in the first centuries B.C., it was understood by cultured speakers from Gibraltar to India. Egyptian, the language of the pyramids and their hieroglyphics, was spoken along the Nile from the dawn of time until the Islamic invasions of the seventh century A.D.; now it survives only in vestigial form, in the dialect of the few remaining Coptic Christians.

Sumerian, one of the first written languages, dominated the Middle East in the third millennium B.C. but was utterly forgotten until its cuneiform script was deciphered by modern linguists. Punic, the language spoken by Rome’s great rival Carthage, has vanished completely: Though Phoenician traders spread it around the Mediterranean, not a single text survives.

As Mr. Ostler shows, the history of language is full of unhappy endings. Indeed, it’s not even clear what a happy ending for a language might look like. At best it might be cryogenically preserved, not living but not quite dead, for the sake of a literary or religious heritage. We still read Greek in order to have access to Plato, for instance, or Pali for the sake of the Buddhist scriptures.

Even in unbroken language traditions like Mandarin and Sanskrit, however, the spoken language diverges so much from the ancient texts as to be practically another tongue. If a language does define, as Mr. Ostler says, “a characteristic viewpoint on the world” – if living in Navajo is different from living in Japanese – then whole modes of being are doomed to die along with the languages that housed them.

Mr. Ostler’s phrase suggests the problems facing his ambitious book. If language is understood as a way of being in the world, then a history of languages must encompass culture, politics, anthropology, religion – in a word, everything that makes human beings human.

By designing “Empires of the Word” as not merely a study of historical linguistics but a “language history of the world” – a 6,000-year chronicle in which the protagonists are not states or peoples, but language groups – Mr. Ostler has essentially set himself the task of writing a history of everything. Not surprisingly, the book that results is disappointing.

In his 14 chapters, Mr. Ostler – a scholar of linguistics who has done research on teaching language to computers and is also the chairman of the Foundation for Endangered Languages – tells the stories of the rise and fall of many of the world’s major tongues. Starting in the Middle East with Akkadian, Egyptian, Aramaic, and Arabic, he moves east to take on Sanskrit and Mandarin, then heads back west to pick up Greek and Latin. In the modern period, he focuses on the languages of European imperialism, primarily English and Spanish, with sidelights on French, Portuguese, and Russian.

Mr. Ostler is not out to explain the formal properties of each of these languages or to summarize their literary achievements. Rather, he wants to track the worldly career of the language over time and space, to explain who spoke it, where, why, and for how long. But since languages don’t exist as Platonic entities, this comes down to offering a thumbnail sketch of the history of each group of speakers: As Mr. Ostler writes, tautologically, “the fundamental point about language spread [is] that it depends on community growth.”

To explain community growth (and decline), Mr. Ostler has to explain the collapse of the Sumerian Empire; and the colonial strategies of the Dutch East India Company; and the role of the Roman Catholic Church in educational policy in Spanish Mexico. The book becomes a sprint through world history, in which disappointingly little is learned about the actual languages. His chapter on Sanskrit, for instance, includes just five pages on “the character of Sanskrit” – not nearly enough to give even a rudimentary sense of that hugely complex subject.

In its style and organization, “Empires of the Word” suggests an author struggling to keep control of his material. But the material itself is always rich, and Mr. Ostler is good at drawing the reader’s attention to its curious corners and unlikely connections. He discusses a stele inscribed in Mandarin and Aramaic, a legacy of early Christian missions; he produces a historical document, the Strasburg Oaths of 842, which offers a snapshot of Latin as it metamorphoses into French. Perhaps the book’s most interesting section deals with the fate of pre-Columbian languages in Mexico and Peru, one of Mr. Ostler’s special areas of expertise. “Empires of the Word” is best approached as a cabinet of curiosities, and an Ozymandias-like prophecy: “Look on my works, ye mighty,” Mr. Ostler’s ruined languages seem to command us, “and despair.”