"The Last Priestess" Deleted Scene! Kinda... · 2:58pm May 16th
While reviewing "The Last Priestess," I realized I'd accidentally deleted a small-but-important line from the text--which is a shame, as it was one of my favorites 
The line has been restored, but, for convenience's sake, I've copy-pasted the relevant passage below. This paragraph comes shortly after Celestia first arrives at the stone circle, when she starts to clean off the stones, and gives more information on the language she speaks:
As she cleaned the stones, she began to sing—quietly, at first, but, before long, her song echoed through the trees. Her voice was high and beautiful, and clear as a bell—though, for most ponies, the words would have been thorny, harsh, and unrecognizable. Only scholars of linguistics would have known it as Old Ponish—not the Ye Olde Ponishe of thees and thous, but Old Ponish, the language spoken by the first ponies to walk these lands, barely removed from the Griffish that inspired it. These linguists would also have recognized the song itself—a harvest-song, rejoicing in the bounty of the earth, while also mourning the end of the year. It was a children’s song, a filly’s song, that Celestia had sung when she, little more than a filly herself, had first cleaned these stones. She had kept up the tradition throughout all the years of her toil.
In Earth terms: Celestia still speaks Old English, the language she spoke as a filly, at least well enough to sing it. Old English is basically German, and is almost incomprehensible to modern listeners--think "Beowulf," not "Hamlet."
(For clarity's sake: Shakespearean English is known as Early Modern English, and is actually pretty closely related to the English we speak today. Most often, the phrase "old English" is used to refer to Early Modern English, but that usage is not correct.)
Yeah, Celestia singing in old Old English is quite an image. I still remember vividly how I dug into it for a month for a similar bit, good times
I got an actual scholar of Old English to help me with a few lines of poetry. She found the pony thing somewhat puzzling, but was happy to help.
There is a definite beauty in the language, hints of which almost makes sense.
I took her singing to be something somewhere between Celtic, Saxon, Danish, and Norse.
I found your descriptions of her following the rituals being somewhere between neo-pagan and neo-heathen traditions, with a little Druidism mixed in.