On: every psalm and song in the daily prayers uses today’s English. Off: all of them use the older “thee and thou”. Until you choose, the Songs of Zechariah, Mary and Simeon use today’s English, as most churches sing them. The Lord’s Prayer and the prayers for the dying show the form most people learned.
The service on the night before Easter Day: new fire, the Exsultet, a series of Old Testament readings, baptisms, and the first Eucharist of Easter. The oldest and fullest service of the Christian year.
In Church year — Seasons, festivals, and the calendar that orders them.