The College of Cardinals decided today that the process of electing a new pope will begin on April 18. All cardinals under the age of 80 will be invited to participate, which means that up to 117 men from all over the world will convene in the Sistine Chapel. What language will they use to speak to one another?
Italian, probably. Most cardinals have spent at least a couple of years studying at one of the pontifical universities in Rome (say, the Pontifical Gregorian University), where they would have had the opportunity to learn and practice Italian. When they were bishops, these men would also have been asked to report to Rome every five years for "ad limina" visits—or planning and prayer meetings with the pope and other officials. Almost every member of the College of Cardinals can understand Italian, and most can speak the language as well.
No one actually knows what language is spoken during the election proceedings—or "conclave"—because the cardinals meet in secret. Not even a translator is permitted to enter the chapel during this time. The cardinals meet by themselves for two votes in the morning and then two more in the afternoon, with a break for lunch. They do have some contact with service staff at the special dormitory in which they stay throughout the conclave, but staff members are not permitted to speak to them.
The official language of the church is still Latin, but use of the language has been in decline ever since the Second Vatican Council of the early 1960s. As a result of those meetings—which were themselves conducted in Latin—the church declared that since the vernacular "may frequently be of great advantage to the people, a wider use may be made of it." Even during that council, there were communication problems among the cardinals: Cardinal Richard Cushing of Boston argued that he and others were being left out of the Latin proceedings, which, he said, were "all Greek to me." At his request, a simultaneous translation system was put in place.
After Italian, the languages most commonly spoken among the cardinals are Spanish and English. But communication may not be so important during the actual voting process. In the Sistine Chapel, the cardinals say very little. They kneel in prayer and make a sworn declaration in Latin as they cast each vote, and then a formal announcement of the outcome is made, possibly also in Latin. Only when the cardinals leave the Sistine Chapel do they converse with one another about the process.
Bonus Explainer: Readers have been asking how the new pope will choose his name. Conventions have varied over the centuries. From early on, many popes changed their names to honor Christian saints or earlier popes, and to show their Christian faith by abandoning pagan names (such as Gerbert). Starting around 1000, the practice became formalized, but the choice of a new name was somewhat political, and popes were often influenced by other church officials. In the 13th century, popes started to choose their names independently. The use of numbers began in the 6th century, when the second Pelagius took the suffix "junior." (He's now referred to as Pelagius II.)
For the last few hundred years, popes have chosen the names of popes they wanted to thank, especially those who helped them rise through the church hierarchy. John Paul I took his double-name to honor two predecessors, John XXIII and Paul VI.
Explainer thanks Monsignor Brian Serme of the Catholic University of America and Salvador Miranda. Thanks also to reader Patti Lenard for asking the question.