I have never flown over there but have often heard that VFR flights need an interpreter.
It's not VFR flights but rather any flights other than from/to international airports (as I wrote above, only FIR/CTA control centres and airports with regular foreign traffic have English-speaking ATCOs), and not just an interpreter but rather a Russian navigator. An "IFR-compliant VFR" flight to ULLI would not require one. However, even at ULLI (visited by scores of foreign airliners every day) the English language skills of some ATCOs are pretty murderous.
This incident led to a serious internal investigation. As it turned out, only the ATC shift supervisor on that day had ICAO level 4. Knowing the system, I don't expect the situation to change very quickly.