Bite your tongue
To refrain from speaking.

Break the ice
To initiate conversation in a social setting.

Call a spade a spade
To speak plainly and directly.

Get the message across
To convey an idea or information clearly.

In the loop
Being informed about something.

Keep someone in the dark
To withhold information from someone.

Read between the lines
To understand the underlying meaning.

Speak your mind
To express your thoughts openly.

Speak of the devil
When the person you are talking about appears.

Take with a grain of salt
To view something with skepticism.

Throw in the towel
To give up or surrender.

A little bird told me
To say that you heard a rumor from someone.

Actions speak louder than words
What someone does is more important than what they say.

Get something off your chest
To express something that has been bothering you.

Mind your language
To be careful about the words you use.

Put your foot in your mouth
To say something embarrassing or inappropriate.

To have a heart-to-heart
To have an honest and serious conversation.

Talk the talk, walk the walk
To back up your words with actions.

Water cooler talk
Casual conversation in the workplace.

Caught in a catch-22
A dilemma with no good solution.