watch your mouth 说话当心点，注意言辞

【例句】
Watch your mouth! I don't care how you speak at home, that's not how we talk here.
说话要注意言辞，我不在意你在家如何说，但是这儿我们不能这样说。

Watch your mouth. Do you know whom you're talking to?
说话注意一点，你知道你在跟谁说话吗？