Explaining Subtlety in English Communication
Generally speaking, unspoken communication is often more important in many parts of the world in comparison to Western cultures.
But that doesn't mean English speakers don't value subtlety when the situation calls for it. In fact, there are a number of common expressions related to things not said directly.
Since many of our students come from Asian countries where such communication tends to be more common, they'll likely appreciate learning some English terms for subtlety. We've prepared a list of some of the most common expressions along with some useful related vocabulary.
Idioms About Subtlety
Read the room

Simple explanation: understand the mood of the people in a space
Make sure to read the room carefully — you don't want to make a joke at the wrong time.
(Read) the writing on the wall
Simple explanation: recognize that something is happening or is about to happen
The writing's on the wall; AI will revolutionize our industry and we need to be prepared for it.
Beat around the bush
Simple explanation: avoid mentioning a topic directly
We don't have time to beat around the bush. Let's discuss the problem so we can find a solution.
(Catch) a vibe

Simple explanation: sense the feeling of a person or a location
This informal expression can be used in either positive or negative ways.
She has a very positive vibe about her and is always pleasant to talk to.
I caught a really bad vibe from John just now. What's wrong with him?
Bonus: "Vibe" can also refer to a unique environment that has been created through decoration, music, etc. This is generally used in a positive and informal way.
Last night's concert was such a vibe. Everyone had a great time.
Written all over one’s face
Simple explanation: emotions that are clear from a person's facial expressions
You like her, don't you? It's written all over your face.
Read between the lines

Simple explanation: recognize clues in order to understand something that has not been said
In business negotiations, being able to read between the lines is a valuable skill.
Broach a topic
Simple explanation: carefully mention a sensitive subject or issue
She wasn't sure how to broach the topic of Sam's illness.
Put out feelers
Simple explanation: check to see how people feel about or react to something
Before investing more money in the project, let's put out some feelers to see if people are interested.
Unwritten rules
Simple explanation: rules or ways of operating that are not clearly written/spoken
Jake broke one of the unwritten rules of the culture when he stuck his chopsticks upright in his bowl of rice.
Understood
Simple explanation: known and agreed upon
It was understood that Kevin would be the leader of the project.
Related Vocabulary
The following adjectives are all useful for describing manners or actions that aren't direct or obvious.
Sly (negative)

The businessman used sly tactics to get an advantage over his competitors.
Cunning (negative)
The cunning salesman convinced customers to buy more than they actually needed.
Understated (neutral-positive)
He usually has a calm and understated personality, but when he drinks, he’s like a totally different person!
Tactful (positive)
How can I tell him the report needs to be improved in a tactful way?
Wrap-up
Subtlety is an important part of communication, both in formal and informal situations. These expressions can help your students talk about subjects that aren't clearly stated but are still significant.
And given that these aren't often taught in textbooks, they can also help learners to sound much more fluent — a win-win!