It seems to me that the speaker is saying something like "Aryst pulchra" by running "ara' and "est" together. Is that intentional?
Linguistically speaking, yes. Grammatically speaking, no. Greek, for example, actually has grammatical rules for elision. There is no elision occurring in the text. Linguistically speaking, yes, he is eliding or slurring his words. And he is hard to understand at times because of this.
English speaker here. We can use "pretty," though it's not the first word that comes to mind, or a word used often to describe such things (in my experience). "Beautiful" seems like a better English word for describing the sacred things. "pretty" seems to describe ephemeral things, while "beautiful" seems to be attached to both permanent and transcendent things. Your mileage may vary, but that's how I've heard the words used.