When Roman Catholic cardinals vote in the Vatican for a new pope next week, they will swear an oath before God in Latin and then cast ballots written in the Church's official language.

Any canvassing for votes or comparing of notes between ballots, though, will almost certainly be done in Italian. Most "princes of the Church" would be lost if a cardinal sidled up to them and began sounding them out in whispered Latin.

The classical language served the Church for centuries as the link among the top Catholic clergy. The 115 cardinals who will elect the next pope come from all corners of the globe and have several dozen mother tongues among them.

But the demise of Latin within the Church, which stopped using it for Mass in 1965 and dropped it at its Rome-based universities for priests soon afterwards, has meant the Vatican's everyday language, Italian, has become the norm.

"We manage to communicate with each other. Most of the cardinals speak Italian," explained London's Cardinal Cormac Murphy-O'Connor, who learned the language fluently as student in Rome in the 1950s. "It would be rare to find one who doesn't."

Many other cardinals picked it up the same way after being sent to Rome for the pontifical university degree or Vatican job that signals a man on his way up the Church career ladder.

Speaking Italian has even become an unwritten requirement for the papacy. Polish-born Pope John Paul won over surprised Roman crowds at St. Peter's Square on the night of his election in 1978 by addressing them right away in fluent Italian.

"I do not know if I can express myself well in your ... our Italian language. If I make a mistake, correct me," he said.

NO JOKES, PLEASE

Given their ages, all but the youngest cardinals would have said Latin prayers at daily Mass before the Second Vatican Council decided in 1965 to switch to local languages.

But reciting texts is easy, conversing off the cuff is hard.

"I joke with cardinals in Latin ... and most don't laugh," Father Reginald Foster, a Latin teacher at the Pontifical Gregorian University here, remarked with clear disapproval. "Some say they have no idea what I'm saying."

Among the few who can is Cardinal Joseph Ratzinger, who is tipped as a frontrunner in the race for the papacy. Some East Europeans have also kept up the tradition, Foster said.

Others try but their Latin "is on the spaghetti side," said Foster, meaning it sounded more Italian, which like French and Spanish developed over the centuries out of Latin. Many Italian and Latin words are so close they are easy to guess.

According to Italian media, most cardinals speaking to the pre-conclave sessions known as the "congregatio generalis" (general congregation) addressed their colleagues in Italian.

They said about one in eight speeches was held in the outside world's international language, English.

While most politicians instinctively reach for the headphones at international meetings, the men who have made it to cardinal rank in the Church are usually linguists who have spent at least several years studying in a foreign country.

Pope John Paul used to speak Polish with his personal secretary, German with main doctrinal specialist, Italian with many cardinals and English, French and Spanish with visitors.

"In Rome, you usually start in Italian," Washington Cardinal Theodore McCarrick said when asked how he communicated with other cardinals. "But many of them speak English.

"I can speak Italian, French, Spanish and German, so I can usually get by," he said. "I really wish I knew Arabic. That would really be great."