I agree. I mis-spoke. English did not shape Christianity. But Christianity shaped English.
The King James version (the first widely available Bible translation in Englsh) was published in 1611, but it is still in widespread use (in the US) today, despite more recent translations. So are Shakespeare's plays, written between 1590 and 1615. Those plays are the bane of every US high-school student (they really can't read 1600 UK English).
Christianity shaped English!?
The Authorised Version is necessarily in English. It was "Appointed to be read in Churches" and the Book of Common payer uses the same language. At the time it came out church attendance was compulsory and when it stopped being compulsory continued to be high. Most people got to hear and continue to hear it today. The language was a bit archaic for its time, but that was deliberate to give it authority when it was read out. Even non-regular churchgoers are fond of it. Whatever you think of the Bible it cannot be denied, as the Bible Gateway says, that "its [theAV's] powerful, majestic style has made it a literary classic, with many of its phrases and expressions embedded in the English language". The many phrases and expressions are embedded because people heard them and writers took them up and repeated them. They are not embedded for any religious reason.
The language of Shakespeare also has a powerful, majestic style with many of its phrases and expressions embedded in the English language having entered the mainstream, mainly through other writers repeating them.
No one would say that the theatre shaped English, so why should they say that Christianity shaped English? The AV and Shakespeare have been influential, but many other factors have helped shape English.
The language of the English speaking inhabitants of North America in 1600 was the same as that spoken in England at the same time. So the US and UK pupils are equally advantaged/disadvantaged when they "do" Shakespeare. I am inclined to think that the difficulties attributed to understanding Shakespeare are exaggerated. Pupils may have a problem with Shakespeare because they come to it believing it is boring. It can be tedious "doing" a play whoever wrote it - plays are meant to be performed and watched, not studied laboriously. The vocabulary may need footnotes for a modern reader, but not to the extent that the flow is interrupted. I have out of interest just read the first scene of
Hamlet and there are only a few words which some may not know. Not all the syntax is modern, but again I cannot see that that significantly prevents comprehension. People today have no problem with negatives being formed by "not" following the verb because it happens in Modern English with the verb "to be" and with auxiliary and modal verbs, as does inversion when forming questions.
I am thy father's spirit,
Doom'd for a certain term to walk the night,
And for the day confined to fast in fires,
Till the foul crimes done in my days of nature
Are burnt and purged away. But that I am forbid
To tell the secrets of my prison-house,
I could a tale unfold whose lightest word
Would harrow up thy soul, freeze thy young blood,
Make thy two eyes, like stars, start from their spheres,
Thy knotted and combined locks to part
And each particular hair to stand on end,
Like quills upon the fretful porpentine:
But this eternal blazon must not be.
I think most people get the drift even if they do not know what "blazon" means.