Silence can mean many things in interpersonal relationships. It's ambiguous. It can express lots of different emotions ranging from joy, happiness, grief, embarrassment to anger, denial, fear, withdrawal of acceptance or love. What it means depends on the context.
When Silence is Golden
Silence can be a very powerful way to "be" with another person, especially when they are troubled. It can communicate acceptance of the other person as they are as of a given moment, and particularly when they have strong feelings like sorrow, fear or anger.
This kind of silence means being willing and able to give the other person your full attention. This includes appropriate eye contact, and gestures like nodding, leaning forward, smiling, frowning, and other facial expressions which let the other person know you really hear them.
Being quiet and not saying anything gives them the space and uninterrupted time to talk about whatever is on their mind. When another person has a decision to make, a problem to solve or simply a need to express themselves, silence can often provide the opportunity for them to have time to talk, reflect and decide without outside pressure.
This is not the same as the "bite your tongue" kind of silence when you want very much to jump in and offer advice or reassurance, ask questions or give your opinion, but you restrain yourself. That kind of silence is full of judgment and indicates that you aren't really listening to them, but instead are focused on your own reactions about what they're saying.
It is essential that the silence be experienced as accepting; people pick up on judgments and evaluation (negative or positive) even when they're communicated silently. If you don't accept the other person as they are, that will most likely be quite apparent to them. And they will be less likely to share their feelings and problems with you at other times.
It goes without saying that silence as a helping skill has a limitation--while it can help others get started talking and help them feel accepted, it doesn't prove that the listener has understood. For that, you'll need Active Listening.
When You Silence Yourself
"Our lives begin to end the day we become silent about things that matter."
Martin Luther King, Jr.
Sometimes we need to speak up and don't do it.
Too frequently, we silence ourselves when we have feelings we think or feel sure the other person won't want to hear. We often do this because we value the relationship and are afraid that it will worsen or even end if we say how we really feel. Ironically, without honest and open dialogue, there is no possibility of a deeper and better relationship. Silencing yourself contributes to the very thing you want to avoid. Further, if it's anger, resentment or another strong negative feeling that you have, keeping silent doesn't make that feeling dissipate. Just the opposite happens--the unspoken problem remains, distancing occurs and the relationship suffers as a result.
At other times, you feel hurt, angry or upset by something another person says or does. Because letting them know how you feel makes you vulnerable, you decide to keep those feelings inside and withhold them from the other person. Sulking, pouting, pursed lips, not answering, abrupt answers, ignoring the other person, giving them the "cold shoulder" are signs of this kind of silence, otherwise known as "the silent treatment." Invariably, the silent treatment is hurtful to everyone involved. Even so, many of us have a tendency to withdraw and withhold when we're in emotional pain, especially from the person we perceive is causing it.
The alternative to the silent treatment doesn't have to be lashing out in anger at the other person. That just causes the problem to escalate and become an even bigger issue than it started out to be. A far better approach is to be willing and able to talk to them honestly about how you feel and why--without blame. For example, let's say your spouse/partner forgot your anniversary (or birthday) which was very hurtful to you. Instead of giving them the silent treatment or lashing out at them, a better alternative would be to say: "I'm so hurt that you didn't remember our anniversary." Or that your boss didn't give you a promotion you thought was a "done deal". Instead of saying nothing and suffering in silence (and resentment), say "I feel very confused and disappointed that I didn't get the promotion that I expected and I'd like to talk with you about it."
When we drop our pretenses and defenses and are authentic in our significant relationships, we experience relief, heightened self-worth and a deeper sense of meaning. It is one of the joys of existence.