You need a bit more information. Are you going with a tour or solo?
I went solo and I don't really know any Russian aside form what I picked up while there. I stayed on the Europe side of the Urals, and bounced between hostels. It is definitely more difficult to go solo, but with some pedimiming and patience, it is easy enough. Contrary to a lot of stereotypes Russians are generally nice, helpful people. I can't tell you how many pairs of nit socks I bough from the babushkas on the streets.
If you smile and point, you should be fine. It really depends on how experienced you are at traveling.
I do, of course, always recommend studying up on the culture and language A BIT before you go. Know some words and carry a dictionary. The 'Where is...(bathroom/police/embassy)' and 'I want...(food/water/beer)' set of words is pretty much required where ever you go.