There were several attempts to compel the Hungarian Greek-Catholics to use Greek instead of Hungarian for the divine services. Father Cyril Korolevsky devotes an entire chapter of his book Living Languages in Catholic Worship to this affair. As things turned out, the only result was that the Institution Narrative at the Divine Liturgy was chanted in Greek, but using the so-called "classical" pronunciation - I heard this done two or three times. After Vatican II, that particular cobweb disappeared and now the services are all entirely in Hungarian.
To this day, there is no complete translation of the service-books into Hungarian, which is a serious inconvenience.
Fr. Serge