Nonverbal communication often has international characteristics that can help with cross-cultural communication. Actually, most communication is done with nonverbal cues, no matter how clear the verbal interaction may be.
Despite cultural differences, there are identifiable universal sounds, facial expressions and body movements that rightly convey a message.
A smile, a frown, crying, all reveal an emotion. How this is interpreted or responded to, rests more with cultural or learned behaviors.
Often nonverbal is the ONLY way to communicate, if there are language differences. Signaling intention, with a smile and a nod of a head is a step towards saying what you would like.
Again, the cultural response may lead to miscommunication. Someone may say to him- or herself "That person should not be smiling at me. They are not someone I know." SO, the interpretation of someone gesturing friendliness or good feelings may be problematic. If there is a language difference, even this negative response will be shown non verbally. All people "get the message" when another walks away or turns away.
In each culture, there are learned explicit gestures that signal dislike, acceptance or some other message. Misinterpreting these can lead to problems. For example, in some cultures, if you want someone to come to you, you wave your hand at them, with the palm of your hand facing the ground. In other cultures, this would be seen as a dismissive gesture.
Even with these problems, nonverbal communication is relied on more and more. As people travel to other countries, meet strangers and embrace cultural diversity, respect and interest in non verbal communication is an excellent starting place to meet others and communicate.
To me, there is a problem with nonverbal communication that neither of the first two answers addresses. The problem is that various nonverbal forms of communication mean different things to people from different cultures.
For example, because of where I grew up, I have a hard time looking other people in the eye. It was considered rude and somewhat aggressive. So I do not make eye contact well, especially with "superiors." In American culture this does not have the same meaning of respect as it does where I grew up.
As a second example, again from my childhood, in those days (I don't know about now) it was acceptable and normal for same-sex friends to hold hands while walking along. If you were to try to hold the hand of a same-sex friend in the US today, people would assume you were homosexual.
Only to a very limited extent do we realize any benefits of non-verbal communication. We have facial expressions suggesting limited emotions, and we can use limited body poses and gestures with hands and feet. But true communication, in which we discuss abstract thoughts and true feelings requires a developed vocabulary and precise grammatical structures. Basic feelings of attraction, longing, sadness, and happiness are esasily espressed through body language. This accounts for foreigners dating native peoples when one does not speak the other's language. But it is extremely limited in discussing dreams, hopes, fears, and requirements for later life.
Non-verbal communication appears to be the most effective way of communicating with people who do not speak any language known to you. As a matter of fact this is the medium of communication which was in use much before development of spoken language as a means of communication.
There can be cultural difference also on the way non-verbal communication is interpreted. But the similarities across cultures are much more than differences. As a matter of fact all humans are born with very good instinctive understanding of some aspects of non-verbal communication. For example, a new born baby is also able to figure by looking at faces of people their feelings such as of love, approval and disapproval.
Non-verbal communication is also relied upon by large organization to communicate with people speaking different languages. For example. international airports use visual signs board to guide passengers on locations of different types of facilities.