When the cardinals meet to choose a new Pope, are their deliberations in Latin? Or Italian? Or what?
I have no expertise beyond catechism, but if I recall, Latin (specifically “Church Latin”) is the official language of the Catholic church and used in all international conferences and such.
Latin. Hence “habemus Papam”.
(Literally, “we have a pope.”)
Latin is the official language of the church, and official documents such as encyclicals are published in Latin, but that doesn’t mean that Latin is the sole language spoken at meetings. It’s pretty much the same as in international organizations. The European Union, for example, has about 20 official languages (every language that is the official language of one of the 25 member states), and there are translators at the more important meetings. But only three languages (English, French, German, but German is hardly ever used in practice) have the status of “working languages,” i.e. languages in which the plethora of minor meetings are held.
I’m confident that pretty much every cardinal has a sound education in Latin, but very few people actually speak Latin fluently. I guess that the cardinals communicate in whatever language is common to the people that try to communicate with each other; as many people in the higher echelons of the church work, or have at some time before, worked in Rome, this can very likely be Italian in most cases. Nonetheless, paperwork in the church is very often done in Latin for reasons of tradition; in the conclave that elects the pope, this is reflected by the phrase “Eligo in summum pontificem” (I elect as supreme pontiff) printed on the ballotts on which the cardinals write the name of their candidate. The proclamation of the newly elected pope to the people is also done in Latin, as has already been said.
I remember a professor at seminary telling a story about a Protestant theologian (I forget who) who was invited to attend Vatican II as an ecumenical observer. Apparently the American bishops were much less practiced at Latin than their European collegues. The Protestant happened to be fluent, however, so they would ask him to recap the events at the end of every session.
Of course, Vatican II was much larger and more diverse in attendance than the papal conclave, there was no other language common (at least in theory) to all of the members, and the official statements and documents being formed and debated were all in Latin. I’d bet that most conversations were held in other languages, though.
My guess is that most Vatican functionaries (not Cardinals) get pretty fluent in “conversational” Latin, just because so much of their work is in Latin. (But conversations about what to order for lunch are probably in Italian.)