Actually, you are possibly witnessing to them right now; as they could be reading this.
And the first thing they will see in many places is that they are worshipping Satan because of the name they use, even moreso than because of the rejection of the Son (which is of course taken as a given, while the name issue is what is emphasized over and over).
Salvation for them is not changing the language one says elohim in, it's solely in recognizing their need for a savior and accepting Jesus as that savior.
If they are reading this, then I guess they've been told they are worshippin satan. It's good for them to know that. Now they can decide to turn from that and worship the one true God.
What does the name or language have to do with anything? I don't remember commenting on that at all.