Digital games are region-free, meaning you can buy and play from a country even if you don’t live there, providing you have a valid method of payment. If you are buying games from a store online, please avoid certain retailers, I won’t name names but be
very careful as they can be stolen games. Buy from reputable and trust worthy companies. If you are worried about who to buy from, buy from the Xbox Store directly. If a deal looks too good to be true, it probably is.
As for the language, The Witcher supports mutiple languages and you can change the language you want to use through the settings. The Russian copy supports: Russian, Czech, Hungarian, English and Polish.
Hope this helps!