For whisper, click on the word "Talk" in your chat bar. In brings up your chat options. The way to "Tell" is to bring up the party list (online list) in your main NWN menu to the right. Click on who you want to send a Tell to, and find the appropriate Icon at the top of the pop-up.
I have had people Tell me somethign that aren't in my party or even in the same area. I have tried to reply to them. For example if morrus has a character by the name of John doe. Who is not in my party is the Tell command /T John doe, or /T <John doe>, or /T "John doe". Also is it case sensative?
I don't know if it's case sensitive, but it should be the following command:
/tp "morrus" text
or
/t "John Doe" text
The quotes are a must if the name is not in one word.
Alternativly you can open the "Player Overview" with game menu <p>, select there a player and than press the "tell" button in the menu of that Dialog.
In your chat bar should now be the correct command+name.
Thanks all I was not putting " around the text as in the NWN manual it doesn't mention this. I got it now. In last couple times I played somone used tell while on a different map and I couldn't respond. Didn't want to appear rude but couldn't use the command properly.