Ask the Jews who use Hebrew, or the Orthodox who use Greek, or Old Slavonic--or the Maronites who use Aramaic.
What sacred language is NOT is 'street language.'
Hebrew, Greek and Old Slavonic are old languages, to be sure.
But they were street languages back at the time of the formation of their respective churches. Greek, Hebrew and Old Slavonic were also used, in their day, to blaspheme and to negotiate porneia.
I dont thing old = sacred.
Nothing wrong with old, but it seems to me that old = old, and sacred is what's said and meant, not which linguistic vehicle is used.