From LSWiki
General-Use Command
Usage: stage-whisper <message> [to <person> [and <person>...]]
[conversationally] [in <language>]
Stage-whispers a message. This is 'pretend whispering' that is as audible
as ordinary speech.
The 'conversationally' option lets any recipients who might interpret what
you're saying as a command know not to do so.
Examples: stage-whisper Uh-oh!
stage-whisper Look who's here! to Bill
Development Information: The stage-whisper command was created by Chaos;
the source code was last updated Mon Jun 18 18:29:38 2018.
See Also: whisper, mumble, say, shout, sing, tell