Maybe. I know that other rats learn to trust quicker when you have more rats that already trust you. I don't think it's verbal though, I think they just show with body language "hey, this person is good" or "hey, don't trust them!"
I don't think its so much what they say as what they do around us - when I got Rauha she basically took her lead from Ilsa. Ilsa will run right up my sleeve when I put my hand in the cage, Rauha just sat there and sniffed my fingers. Ilsa then came back down my sleeve and obviously said something to Rauha about how this was the way to get on board the giant rat, and led Rauha back up my sleeve. I'm sure that rats learn from watching other rats, and if one rat can see that the other rat is absolutely fine and hasn't been eaten then there is a good chance that they will follow their buddies lead.