/say - Say something to anyone in your local area /s - Same as /say /groupsay - Say something to members of your group /group - Same as /groupsay /g - Same as /groupsay /party - Same as /groupsay /p - Same as /groupsay /tell [name] - Send a private message to another person (use quotes around names with a space) /t - Same as /tell /reply - Send a private message to the last person that sent you a private message /r - Same as /reply /shout - Shout a message to everyone in the same region (like say but broader). A shout in Gotham won't be heard in Metropolis and vise-versa /invite [name] - Invite another person to join a group with you (no quotes needed) /leave - Leave your current group /kick [name] - Kick the specified person from your group (no quotes needed; must be leader) /promote [name] - Promote the specified person to be the group leader (no quotes needed; must be leader) /pvp - Set yourself up for PvP while you're on a PvE server (both players need to have it set).
Note that none of those (afaik) work to communicate with the opposite faction, villains won't hear shouts from heroes and vise-versa, I believe they don't heir /say either. And last time I used /tell it said "blocked to other faction".
IF you've ever played WoW, you would know. It's the same as every MMO game. Try doing /dance and who knows? Maybe your character will dance LOL! It's like that in WoW. So I wouldn't be surprised if it worked here.