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.
Praying to saints for intercession. Lutherans honour the saints as examples and give thanks for them, but do not pray to them, holding that Christ is the one mediator.
In Doctrine — What Lutherans teach, and where it differs from neighbouring traditions.