"In accordance with the centuries-old tradition of the Latin rite, the Latin language is to be retained by clerics in the divine office. But in individual cases the ordinary has the power of granting the use of a vernacular translation to those clerics for whom the use of Latin constitutes a grave obstacle to their praying the office properly. The vernacular version, however, must be one that is drawn up according to the provision of Art. 36."
-Sacrosanctum Concilium,no. 101.
I had heard that Vatican II required priests and deacons to say the office in Latin unless given permission by the Bishop, but thought it was unsubstantiated and probably untrue.
I retract that claim now.
"96. Clerics not bound to office in choir, if they are in major orders, are bound to pray the entire office every day, either in common or individually, as laid down in Art. 89."
-Sacrosanctum Concilium, no. 96
I had been told that clerics only had to recite lauds and vespers, and that all other hours were optional. Now I see that that's not true either.