Church Slavic Language

Which countries speak language long out of use except in prayers and lithurgies? I mean Tserkovnoslavyansky language. Does any Slavic nation speak like Az yesm' (I am) , Ty yesi (you are), On yest' (He is) etc. -I mean the verb "to be" in present form?
Do you know Slavic languages that still use obsolete tenses like Aorit, Perfect, Imperfect, Plusquamperfect of Church Slavic Language?

С Рождеством Христовым и С наступающим Новым Годом
S Roždestvom Khristovym i S nastupayuščim Novym Godom

Честита Коледа!

for yesterday....

There are some grammatical calques, as I know, in Romanian, especially older and liturgical Romanian.
Even the fact that Romanian conserved a more synthetic carachter can be, attributed to a certain extent to the Slavonic language.
As for the words, there are plenty.

Literary Serbo-Croatian based standards, Bulgarian and Macedonian all use aorist, imperfect, plusquamperfect. In Croatian everyday speech only perfect tense is used though:

Aorist: On skoči - He had (just) jumped
Imperfect: On skakaše - He kept jumping
Plusquamperfect: On je bio skočio/ On bijaše skočio - He had jumped
Perfect: On je skočio - He jumped

As far as I know, Bulgarians still use Аз for "I, me" and Church Slavinic is actually ancient Bulgarian, if I'm not mistaken...

Linguist, you're absolutely right.