Old material for the Clan Invasion talks about the Clans having a special "battle language" that made use of code words and so on that rendered Inner Sphere attempts to tap their communications pointless; even if they could ovecome the Clans' superior scrambling, they had no idea what anyone was saying.
Presumably, the Scorpions have a more evolved version of that which makes it harder or impossible for non-Scorpions to understand what they are saying, even if they are Clan.
As far as MWGttC goes, the Scorpions don't get Russian. I was very surprised that the Wolves did not either, as many (if not most) of their warriors spend a great deal of time studying the original writings of the Kerenskys. IMO Russian should be a Clan-wide Secondary Language for that reason, with the Wolves gaining a small bonus to it because of their additional interest.
Your mileage may vary.