I'm not usually one for starting threads, but I really wanted to share this video with you all:
I believe the chant is in Bulgarian, though it may be in Church Slavonic. The chant appears to be in the Greek style.
As far as I can tell, the video runs from "the grace of our Lord"/"i haris tou Kyriou imon" through to "we praise Thee"/"Se ymnoumen".
Thanks for posting. It does sound like Slavonic, though I certainly couldn't tell the difference if it was in Bulgarian.
It's in Byzantine Plagal of the First Mode (or perhaps the authentic first mode). My parish sometimes uses an almost identical setting in English.
And yes, the priest has a nice strong Slavic voice........