BENEDICT XVI became the first Pope to abdicate the papacy since 1415 when he announced his decision to retire at the end of February, saying that he is too old to continue. In many ways he has been a reformer. @Pontifex, the Pope's official English-language Twitter feed, was launched on December 12th, along with seven other versions. The Vatican later added Latin to the roster. From Benoît XVI (French) to بندكتس السادس عشر (Arabic), nuggets such as "Mary is filled with joy on learning that she is to be the mother of Jesus, God’s Son made man" have been miraculously popular; the Pope has amassed 2.8m Twitter followers. (@Pontifex follows only the other eight official, non-English papal feeds.) The Pew Forum of Religion and Public Life reckons that there are a total of 1.1 billion Catholics across the globe. A back-of-the-envelope estimate by The Economist puts approximately 900m speaking one of the nine languages that the Pope tweets in. That's one Twitter follower for every 320 Catholics. Jesus would be proud.
The Pope's departure itself was linguistically notable: he announced it in Latin, and one Latin-speaking reporter scooped her colleagues to break the news. The Vatican City’s only official language is Italian (although the Holy See works in Latin), and most of the world’s Catholics speak other languages, like Spanish or Portuguese. Benedict’s native language is German. If the Pope wanted an immediate reaction, he should have made his announcement in a different language. His Latin Twitter account has just 18,500 followers, after all. But the Pope’s use of Latin isn’t surprising. Latin has endured in the Catholic Church as a liturgical language, much like Hebrew (once dead, now thriving) in Judaism or Sanskrit (dead, but used ritually) in Hinduism. Latin education in schools might be declining, but the Vatican gives hope to Latin teachers everywhere. 

What’s more interesting is the choice of languages the Holy See offered official translations for: French, English, German, Italian, Polish, Portuguese and Spanish. Much of the Catholic Church’s recent growth has been in Latin America and Africa. The use of Portuguese, Spanish, and English makes sense for outreach in the Americas. French might be useful for western and central Africa’s elites, but many people in officially Francophone countries don't speak French. Missing from this list is Arabic, which the Pope tweets in. The Pope’sbiweekly catechesis is provided in Arabic, but the weekly "Words of the Holy Father" typically omit the language. Translations in Croatian, spoken by 3.9m Catholics, are sometimes also available. According to our numbers, the Pope’s nine languages on Twitter represent 900m Catholics. Croatian is the only language not on Twitter while regularly available on the Vatican’s website.
The next Pope might want to expand the Vatican’s translation services beyond European languages and Arabic. The Democratic Republic of the Congo is home to 31.2m Catholics who speak French as well as Lingala, Tshiluba, Swahili, and Kikongo (and dozens more). Some of these languages might have more Catholic speakers than, say, Croatian does. Kinyarwanda, spoken by roughly 5.3m Catholics in Rwanda, certainly does. Reaching a potential 900m Catholics is efficient Twittering. But as it chooses a new leader, the Vatican might like to think about creatively expanding its reach beyond its traditional language catalog.