“Vatican officials say he decided to speak English in Congress (and the White House) because he wanted to speak the primary language of the United States in what he called the houses of the people of the United States.
The Rev. Manuel Dorantes, a member of the Vatican press office, said Francis used the slow month of July to bone up on his English, bringing in his interpreter, Msgr. Mark Miles, as a tutor. Vatican officials told the pope to speak slowly so that people could better understand him.
Francis similarly tailored other languages for other speeches. When he addressed the American bishops, he did so as the Bishop of Rome. So he spoke Italian. (It is also true that many American bishops don’t speak Spanish, had the pope chosen his native language.) And when Francis spoke for the canonization of the Rev. Junipero Serra, he went with Spanish.”
Read more @ http://www.nytimes.com/live/pope-visit-2015/francis-struggle-with-english-and-his-decision-to-speak-it/
Languages do matter!
Language Matters 