After 40 years of praying in exactly the same way, English-speaking Catholics around the world had a challenge waiting for them Sunday when they turned up to Mass.
The Mass liturgy, or the text of the most sacred Roman Catholic rite, has been re-launched across the English-speaking world to comply with the Vatican's wish for a more traditional and spiritual tone.
At Saint Monica's, an impressive neo-Gothic church in New York City, parishioners clearly struggled to adapt to the discreet shifts in language laid out on a neatly printed pamphlet.
For decades, when the priest declared, "The Lord be with you," the congregation would reply: "And also with you." This was so ingrained that although the pamphlet instructed in bold that the response was now, "And with your spirit," few managed to make the switch.
Priests, who have far more to say during Mass and know their parts by heart, were having to tiptoe through the texts.
"It will probably take four weeks for the priests to get used to the rhythm," Monsignor Thomas Modugno told AFP afterwards. "It's easier for the people. It's hard for us priests: you get distracted for a moment and automatically you go back to the old version."
The new wording reflects years of work and negotiation involving English-majority Catholic communities from the United States to Europe and Africa to Asia.
Changes are frequent, but small, rather than structural. There is nothing on the scale of the revolution brought by the Vatican's abandonment in the 1960s of the centuries-old Latin Mass.
However, church officials say they want to restore some of the linguistic spirit of that old Mass by tweaking the English translation to reflect more accurately the meanings and cadences of the ancient Latin language.
The results have been criticized by some Catholics as unnecessarily archaic-sounding and confusing.
The Cleveland.com news site quoted one outspoken bishop, Donald Trautman from Pennsylvania, complaining that the alternations introduce a "jumble of subordinate clauses" that threaten "pastoral disaster."
In the previous version of the Nicene Creed, a key prayer for Catholics, Jesus was described as "begotten, not made, one in Being with the Father." Now he is "begotten, not made, consubstantial with the Father."
The word "consubstantial" has come in for particular ridicule from critics, but church leaders say it precisely describes the mystical link between Jesus and the Father within the Trinity.
Modugno said the changes made the Mass "more poetic, inclusive and serious and they bring home the essentials of our faith." More rigorous translation from the original Latin ensured "sacredness," he said.
Parishioners seemed generally welcoming once they got over the confusion.
"I thought it was fine. It was more Catholic," said Susan Kingston, 79. "But they didn't announce that the leaflets with the changes were in the pews. They should have announced that."
Another churchgoer, who asked not to be named, said the new Mass was "fine, if a little confusing."
"I think it would be important to explain what's important in the Mass -- to explain why they had to change it," he said. "Still it's so much based on ritual that the more you do it the easier it gets."
Bishops from the United States, Australia, Canada, England and Wales, India, Ireland, New Zealand, Pakistan, the Philippines, Scotland, and South Africa, took part in the changes.
In some countries, the new version had already begun to be phased in ahead of Sunday, when the entry of the United States was meant to complete the change-over.
French, Spanish versions of the Mass are not affected, in part because they already stick more closely to the original Latin in which they are rooted.
