When choosing a language to study, most of us tend toward the practical. We may wish to be able to converse in Spanish because a significant percentage of U.S. citizens speak that language. We may be planning a trip to France, and would enjoy speaking French fluently enough that even Parisians would not feel offended for their native tongue. Or we may want to know enough Chinese, Japanese or other Asian language to conduct business with people in that part of the world.

But some people home in on languages that have no obvious use in today's world. These are the scholars who devote their time to learning tongues that either haven't been spoken in thousands of years, or that are swiftly on the decline.

To understand the motivation to pore over ancient writings, some of which can only be found on faded clay tablets, it helps to consider the fact that Western society today, with its rich store of professions, philosophies, and religions, owes a great debt to the ancients of Mesopotamia, and to more recent ancestors of European descent.

Economics as a discipline got its start in Mesopotamia, springing from a need to deal equitably with rare resources, such as water. Four thousand years ago, the people of these Near Eastern lands -- such as modern-day Syria, Iraq, and Iran -- also developed the first ''encyclopedias,'' which were extensive lists, iterating types of professions, rocks, animals, and plants. Legal codes, too, were first written in this part of the world. That of Hammurabi (about 1800 B.C.) governed Assyria and Mesopotamia.

More recently, Jews in the Warsaw ghetto painstakingly documented, in Yiddish, the events occurring in their midst at the hands of the Nazis. The aim of their project was not only to point a finger at the enemy, but to present the information as objectively and comprehensively as possible.

We know of these erstwhile secrets of the past because scholars investigate languages, like Akkadian and Amharic, Old Persian and Avestan, that have fallen into complete disuse or, as in the case of Yiddish, are eroding from common use.

While the study of these languages may not constitute the academic road most traveled, the scholars from the Department of Near Eastern Languages and Civilizations who plumb their depths say they find therein a clear view of humanity, its nature and its multiplicity of cultures.

Iranian studies, for example, ''have much to contribute to our understanding of Western culture,'' says P. Oktor Skjaervo, the Aga Khan Professor of Iranian. ''The Iranian language is part of the Indo-European group of languages, and so it is related to English. Iranian culture and our Western culture are historically closely inter-related, and so the study of Western history is connected with that of Iranian literature.''

Western religions, too, have been strongly influenced by the ancient Iranian religions of Zoroastrianism and Manicheism.

''Zoroastrianism is one of the very few religions that originated 4,000 years ago,'' Skjaervo notes. ''But we rarely see anything about it, presumably because the texts are difficult to access.''

Studying such texts ''helps you understand how people think,'' Skjaervo notes. It's intriguing, he says, to ponder the fact that the ancients ''had the same problems we have today. You can see what their value systems were and how they dealt with their problems, and you can see that things haven't changed much over the centuries.''

Religiously and culturally the West has also, of course, been enormously influenced by Jewish culture.

''Yiddish, as the vernacular language of Jewish culture for 800 years, contains very important information about how Europe developed,'' says Ruth Wisse, the Martin Peretz Professor of Yiddish Literature and professor of comparative literature.

Knowledge of ancient as well as modern cultures, through their languages, also helps to preserve our society's diversity, Wisse notes.

''To the extent we can have a pluralistic country, we must study the humanities. And it falls to the universities to prepare the next generation of scholars to carry on these studies.''

John Huehnergard, professor of Semitic philology, teaches languages such as ancient Akkadian (spoken by the Babylonians and Assyrians), Aramaic, Amharic (the national language of ancient Ethiopia), Arabic, and Hebrew.

Knowledge of such languages opens the original texts to study. And this is important, says Huehnergard, ''because the texts make available direct insights into how the people saw the world, themselves, and others. Every culture we can recapture through the texts provides another piece of the puzzle about who we are, about the development of humanity.''

''It's traditional for people in my department to say that Western civilization has been greatly influenced by the Bible,'' Huehnergard adds with a smile. ''The world of the Bible was the Near East -- so the more we understand the Bible and the history and culture of the Near East, the more we understand the development of Western culture.''

As enriching as these subjects are, there are relatively few places where students -- and professors -- can turn to grapple with, contemplate, and delve into the mysteries of language, finding therein keen insights into our collective persona.

''I have to pinch myself to realize that I get to teach this wonderful stuff,'' comments Huehnergard. "I think we lose a lot if we lose the humanities, and it's marvelous that Harvard supports the humanities as much as it does. We'd be so much poorer without the knowledge of who we are, and where we come from.''