On Fri, 16 Sep 2011 13:54:57 -0700 (PDT), Masa <
aut...@infoseek.jp>
wrote:
The origin of "pipe down", meaning to be quiet, goes back to sailing
ship days according to the Word Detective:
PIPE DOWN: "Pipe down," meaning "to be quiet" or "settle down," is so
often used by parents or teachers confronted with a room full of
unruly children that most folks would never guess that the phrase was
born in the days of sailing ships. The pipe in question was the
boatswain's pipe, a small whistle-like device used by the boatswain
(also known as the "bosun," the petty officer in charge of the deck)
to communicate orders to the crew via different arrangements of notes.
When the bosun "piped down" aboard ship, he blew the signal for the
crew to retire from their tasks or formation and return to their
quarters belowdecks. Since the deck would become suddenly quiet when
the crew retired, "pipe down" came to be used as nautical slang for
"be quiet" or "shut up," and by the end of the 19th century it had
percolated out into its modern non-seafaring usage.
To "pipe up", or to "pipe in", meaning the opposite of "pipe down", is
assumably from that usage.
Rather than an analogy, think of "spoke up" as a replacement term.