somewhat dubious one
A new barman gets a job in a pub next door to a day-centre for the deaf and dumb.
The Governor takes him through all his duties and teaches him the signs for all the drinks - crossed hands - pint of beer, two fingers three inches above one another - small whiskey, - four inches above each other - large whiskey... etc.
Rather nervous, he makes a start on the first morning - and flies it.... not a single mistake during the entire day.
Come closing time at three oclock, he goes into the crowded bar to call "time" - total silence, but every single customer is standing or sitting and swinging their hands up to shoulder height in perfect rhythm with each other.
Puzzled, he walks into the lounge, only to find that exactly the same is happening - silence, but all hands being swung up and down in rhythm.
In a panic, he seeks out the Governor and explains what's happening.
"Oh shit" says the Governor, "we'll never get them home now they've started to sing".
Jim Carroll