Here are some options:
Polite:
* เงียบๆ หน่อย (ngiab ngiab noi): This literally translates to "be quiet a little," which is a softer way to ask someone to be quiet.
* หยุดพูด (yut phoot): This means "stop talking" and is a more direct but still polite way to ask someone to stop.
Informal:
* เงียบ (ngiab): This simply means "quiet" and can be used with close friends or family.
* เงียบปาก (ngiab pak): This translates to "shut your mouth" and is more direct, but can be considered rude depending on the context.
It's essential to consider the context and your relationship with the person you're talking to before choosing the right phrase.
It's always best to use a more polite and respectful tone when communicating with someone.