Looks like Rome's chief Latinist may be wrong about B16's "Motu Proprio". But that doesn't necessarily mean he is wrong about Latin being a dead language. As many people know, I attended a Roman Catholic seminary, and let me tell you, they do not study Latin at many U.S. Catholic seminaries, neither do they actively promote it... not because they have anything against it, but because there is only so much time one can be in seminary, and only so many subjects a person has studied. At my school most of my classmates were required to take Spanish, because of the huge pastoral need. They didn't take Latin (which was only offered sporadically), or Greek... and much less Hebrew! There just was not enough time to take all of those extra classes. Nowadays, in addition to the ever-present philosophy requirements (though they too have been streamlined quite a bit), Catholic seminarians have to take several semesters of preaching, catechesis, counseling, professional ethics, social justice, etc. in addition to the Biblical studies, Church history, systematic and fundamental theology, etc. And so, there is only so much time available to take other courses. Eventually you have to graduate, and get out there to minister! So is Latin truly dead? Are they just too busy teaching other desperately needed courses to fit it into the schedule? Time will tell, I guess.
I think that a language like Latin or Greek is dead only if you make it dead. A seminarian can always study those langauges on his own, or take a summer course to at least get him going for private study. And when he graduates it is incumbent upon him to stay with those languages and keep using them and studying them, just as he must continue reading and studying theology, scripture, etc. I study my Latin regularly, and use my Greek everytime I prepare sermons, and I do that on purpose (so I don't forget it). That is how a language stays alive. Even if the leadership at Catholic seminaries does not teach the language for lack of time, they can at least create a favorable and enouraging environment to promote the study of it, and urge seminarians to pursue it on their own. We Anglicans, by the way, should also study Latin, even though we have our own liturgical language. It is the theological language of the western Church, and knowing it even on a small level enriches theolgical study and devotion in manifold ways. But again, there are no Latin police out there to make sure we do that. We must do it on our own, so it stays alive to us, and so we can reap its benefits.