Some acceptable ways Please be quiet. Would you please be quiet? Could I ask you to be quiet please? Shhh! (While holding one's index finger to one's lips!)

I'm not sure if this is a British thing or not, but, to be polite, we start with a 'Sorry, but...' Then, in ascending order of politeness: Can you keep the noise down? Could you keep the noise down? Do you mind keeping the noise down? Would you mind keeping the noise down (a bit) ? Could I ask you to keep the noise down (a bit/a little) ?

'shut up ' ,, oh no that is not the polite version ;) Use words like Please and do you mind with some decent gestures . It works !

Do you mind keep it down?

please be quiet? :D