Stella Ting-Toomey describes three ways in which culture interferes with effective cross-cultural understanding. First is what she calls "cognitive constraints." These are the frames of reference or world views that provide a backdrop that all new information is compared to or inserted into.
Second are "behavior constraints." Each culture has its own rules about proper behavior which affect verbal and nonverbal communication. Whether one looks the other person in the eye-or not; whether one says what one means overtly or talks around the issue; how close the people stand to each other when they are talking--all of these and many more are rules of politeness which differ from culture to culture.
Ting-Toomey's third factor is "emotional constraints." Different cultures regulate the display of emotion differently. Some cultures get very emotional when they are debating an issue. They yell, they cry, they exhibit their anger, fear, frustration, and other feelings openly. Other cultures try to keep their emotions hidden, exhibiting or sharing only the "rational" or factual aspects of the situation.
All of these differences tend to lead to communication problems. If the people involved are not aware of the potential for such problems, they are even more likely to fall victim to them, although it takes more than awareness to overcome these problems and communicate effectively across cultures.