whisper

The whisper command is used to speak privately to an individual in the 
same room. Use the page command to speak to an individual who may be 
located anywhere in the MUD. The . command is a shorthand for whisper. If 
the first character of your text is a : (colon), then you will privately 
pose your text to the recipient. Also, if you use the full version of 
whisper, you can whisper to multiple people at once by giving list of 
names separated by commas or spaces.

Usage:

whisper person = message
whisper person, person, person = message
.person message