When America's Catholic bishops approved changes to the English version of the Mass this month, they showed how hard it is to do any translation.

The Mass is the most sacred of Catholic rites, and any argument about its form has a lot to do with theology. But in this case, the debate is also about the balance of power between local bishops and the Vatican, which ordered the changes — ostensibly to make the English-language Mass truer to the Latin from which it is translated. (The Vatican must still approve the changes adopted by the U.S. Conference of Catholic Bishops.)

But beyond faith and church politics is the challenge of taking Latin passages, themselves often translated from even more ancient Hebrew or Greek, and rendering them understandable to modern worshippers.

The Catholic Church did not lack for Latin scholars in the 1970s, when the current English translation was approved. And yet, that version came under attack from traditionalists from the moment it appeared. They complained that the translation was too conversational and not faithful enough to the original. Many of the changes adopted this month are responses to these conservative criticisms.

One of those troubled by the 1970s translations was a young German priest, Joseph Ratzinger, now Pope Benedict XVI. Last November, the pope expressed hope that a new and more accurate English version of the Mass would be completed soon.

But this month's vote by the U.S. bishops wasn't just the result of a new pope cracking the whip. The command that vernacular translations of the Mass be more literally rendered from the Latin was first issued in 2001, under Pope John Paul II.

The Catholic Mass commemorates Jesus' command to his disciples during the Last Supper to share bread and wine — "this is my body ... this is my blood ... " — in his memory. ("Mass" is derived from a Latin word that means "to dismiss," referring, some scholars say, to the early church practice of sending away nonmembers before the Eucharistic ceremony.)

Church records from the second century describe Christians performing a Mass-like rite in Greek. By the sixth century, a Latin version was in use, with the same basic elements found at a modern Mass. The wording was tinkered with over the centuries, with the most significant revision before the 20th century approved by the Council of Trent in the mid-1500s.

Vatican II, a major conference of the world's Catholic bishops, opened the door in 1963 for the first official versions of the Mass in languages other than Latin.

A body of bishops from English-speaking nations, the International Commission on English in the Liturgy, was formed to produce a translation. The result, used today in American churches, was immediately attacked by traditionalists.

In 2001, the Vatican agreed with the criticisms, saying the translations produced by the ICEL weren't authentic enough. The leadership was replaced, and the commission was ordered to come up with a more literal version.

The American bishops' vote this month was mostly on the suggestions made by the ICEL. Most adopted overwhelmingly.

American Catholics don't have to fret just yet about learning new language. Vatican ratification of the decision could take several years.

How hard can it be to translate even one sentence?

Consider this line from the Latin Mass, spoken by the congregation to the priest: "Et cum spiritu tuo."

The 1970s translation rendered that line, "And also with you." The newest revision: "And with your spirit."

One need not be a linguist to figure that the Latin says something about spirit. So was the 1970s version just wrong?

No, said Matthew Ogilvie, director of preministry studies at the University of Dallas, the Catholic university in Irving.

"Thirty years ago, when they were translating the Mass, there was a huge push to make things understandable in the ordinary language," he said. "I think that was insightful."