Put a sock in it

This is a colloquial British phrase that originated in the early 20th century. It is generally used when someone is being so noisy as to annoy others. The imagery behind the phrases is that putting a sock in whatever was causing the noise would quieten it down. What that thing was isn’t known. There are suggestions that this may have been the horn of an early gramophone or, more straightforwardly, the raucous person’s mouth.

The earliest example of it in print that I can find is a definition of the term in the weekly literary review The Athenaeum 1919:

“The expression ‘Put a sock in it’, meaning ‘Leave off talking, singing or shouting’.”

The fact that an erudite publication saw fit to define the term suggests it was recently coined in 1919.