[CiD]

I believe most of the multiplayer commands, like instamsg_group_x, I found just looking through cgamex86.dll with my hex editor. Some of the commands have comments in the file as well.
Unfortunately, I think that most of the code to execute the DM voice messages is compiled.
As far as I could tell from looking around is the menus themselves are just .tga files that are loaded as part of the hud. That seems to me that the menus were never meant to be very dynamic.
I guess you could put together an alias yourself that does basically the same as the voice commands. Maybe play the sound you want and then execute a say command instead of a sayteam. But then you would not have the dynamic ability of the voice classes that are assigned to the models, like axis5, airborne, ranger, etc. because you would be stuck w/ one sound.