Socio-cultural background makes communication effective.

Effective communication is the communication that results in accordance with the expectations of people who do the communication. For example, sellers who come to the house to offer goods deemed to have effective communication if the host wanted to buy stuff. But in reality, not like that. No human being the exact same, even humans who are born twins still differ in some respects. Human lebh interested to communicate with people who have in common with him. For example language similarities. Common language enables humans to communicate easily, and get the same sense.

A poor man can marry with beautifull girl, a college graduate can be good friends with an elementary school graduate, a white man can have relationships with black people. It all happened because they feel they have a similarity in some respects and can accept the differences of each. A message, verbal or nonverbal basically bound culture. A story of humor can make people laugh, but also can make people feel bored.