all ground to pilot and pilot to.ground communication everywhere in the entire world is in English specifically aviation English it is the official language of aviation. Every pilot that gets a license is required to pass an aviation English proficiency exam. every nation that is a member state of the IACO also ensures that every pilot it has can converse to ATC in aviation English, Russia is a member of the IACO which is civilian but its military pilots are held to the same standards, most of Russia’s civil aviation pilots are former military members as well.
I’ve looked it up and concur...