The Russian Orthodox Church uses Old Church Slavonic as its liturgical language, a language as different from modern Russian as Latin is from Latin American Spanish.
The Greek Orthodox Church uses the liturgy of St. James - using a Greek which is alien and almost incomprehensible to any Greek person who has not grown up in the Church.
The Hebrew used in synagogues from Christ's day to our own was a different language from the common tongue of Jews. As we know, Christ spoke Aramaic and most European Jews spoke Yiddish or Ladino. Hebrew was only recently revived as a spoken, rather than a liturgical, language. Most Orthodox Jews consider Hebrew to be holy in itself - that it is a language directly given by God to man, the language that God speaks and that the letters of the Hebrew alefbet itself were the tools that God used to create the universe.
And for a good three or four centuries many English and German Protestants used the KJV or Lutherbibel exclusively in their worship services - and there was quite a fight in many congregations about scrapping a dialect that no living person had spoken for three hundred years.
I'm glad I don't have to worship in a different language in Church. Apparently, the majority of Catholics felt the same which seemingly is why Vatican II decided to do away with the requirement. This was my original point.
Forgive me if I don't check back to see if you've responded to my post. Things are picking up here and I will be extremely busy for the next while. All the best.