For the curious:
At one parish I know: almost 100% english. Whether it's modern or not depends on where they get their translation from - the parish's jurisdiction uses modern English in its translation, but the parish uses HTM's menaion, some music from St. Anthony's (which also seems to use HTM's translation) and some from the Antiochians/Boston Byzantine Choir. So Orthros and Vespers there mixes traditional and modern English.
A few other places I've been to:
- at a local GOA parish, Orthros for Sunday plus Apodosis of the Dormition was mostly in Greek, with the Gospel in English (previously, I believe there was about 75% Greek/25% English at Orthros, including some of the Kathimsa, Expaostilaria, etc. from Saint Gregory Palamas Monastery's translation). Divine Liturgy goes back and forth between Greek and English, mostly Greek. The Akathist, as I recall, mixed English and Greek 50/50. Holy Friday Orthros was also about 50/50.
- the GOA parish in Honolulu uses mostly English.
- a GOA parish I went to in a certain part of the NE US made me feel that I was teleported back to Greece - even the homily was in Greek, without any English!!! There were even a few young men at the kilros, and the four men up there split up Orthros and Divine Liturgy evenly.
- Monastery of Saint Neilos of Calabria, Italo-Greek Catholic Church: some Italian, but the parts of Orthros that required prosomia were in Greek. As I recall, Divine Liturgy mixed Italian and Greek. [this is just outside Rome, and was founded by the Italo-Greek Saint Neilos around 1000AD. He's commemorated in both the Orthodox and Catholic Churches]