Unseen translation device or telepathy depending on the situation and Zedevic in question.  Only more advanced Zedevics use telepathy towards other species, however.  (Telepathy between zedevics is somewhat more common and is a universal in Nelenn's group).

The general motif with my species is that they will try to spread their faith, but not by force.  In rimspace they likely will outsource their abilities in exchange for favors and/or technology along with seeking positive diplomatic ties with their cousins.  So Zedevic activity is likely fine since they don't rely on force.