Culture informs communication. It brings understanding to communication through a common background of shared experiences and histories. The people of a unique culture usually share a geographic location as well. This common geography also affects the unity of the group in that they will all share the same experiences of weather and topography. Shared experiences over hundreds or even thousands of years create culture that contributes to understanding and communication.
Culture often includes a basic set of shared values and beliefs. In her book "Culturally Speaking," Helen Spencer-Oatey explores the interactive aspects of cross-cultural communication. The shared assumptions of a group of people help to interpret the behavior and words of those in and outside the group. When people have experiences in common this contributes to understanding on a deeper level than what can be interpreted by an outsider. Gestures and idiomatic phrases are often misunderstood by those outside the culture. Although people can communicate effectively with other cultures, they must make an effort to understand the culture as well as the language of the people they communicate with. Culture enhances communication, and this is why people usually understand those of similar background best. As the world shrinks, cultural understanding becomes more important. Although English has become a language of interpretation, its use as a bridge cannot replace cultural understanding as a part of true communication.