The Cubana IL62Ms that I used to work at STN had Cyrillic lettering on the flightdeck and English/Spanish in the cabin although later French signs appeared in the cabins. Certainly on the limited number of Interflug aircraft I worked the flightdeck legends were always Cyrillic with a few German labels on certain items/switches. Aeroflot aircraft were all Cyrillic as were most of the east-bloc carriers except Tarom which had Romanian signage on most items on the flightdeck. Hope this info useful.