Code switching is when people switch, or change, from one language to another while speaking. They might begin a conversation in one language and then, later in the conversation, switch to another. They might also begin a sentence in one language but end it in another. Or they might insert a word or phrase from another language. When and why people code switch depends on the speakers and the situation. One reason people code switch is to show social closeness. Imagine that two women meet at a party in New York. Gabriela is Brazilian, and Pamela is British. In their conversation, Pamela asks. Pamela: Where are you from? Gabriela: Rio. Pamela: Really? Uma cidade muito bonita [A beautiful city] I was there last year. Gabriela: Oh, do you speak Portuguese? Pamela: Um pouco [only a little]… Here, Pamela uses a little Portuguese in order to show closeness or friendliness to Gabriela. On the other hand, people also code switch to create social distance. Sometimes this happens in immigrant homes in the United States where the children can speak English, but the parents understand only the language of their native country. Children can code switch to keep their parents from understanding everything they say. Likewise, parents may code switch when they share a language that their children do not understand. One final reason that people code switch is lack of knowledge about a language or lack of attention to one's language. Imagine a teenage girl living in a Latino community in Los Angeles. Talking with her friends, she says. 'Esperate [Wait a minute] What did you just say?' It is possible that the teenager was not trying to show social closeness or distance. Perhaps she didn't know how to express the second idea in Spanish. Most likely, she may simply have switched to English without paying much attention to which language she was using. Code switching occurs between people who share more than one common language however, it can also occur between people who share a language and a dialect, or variation, of that language. A person may use one dialect at home and then switch to another dialect at school or work. One example is the way teenagers use slang when talking to their friends. For instance, a teen might say to his friend, 'Gotta bounce. Me 'n' the crew're goin' shoppin' for some mad phat gear.' Gotta bounce means 'I have to leave'. 'The crew' means 'my friends' and 'mad phat gear' means 'nice clothes'. Therefore, the teen is saying, 'I'm going shopping with friends'. But only speakers of both English and this teen dialect can understand. Teens use their dialect because it helps them to show that they fit in with their friends. It also shows that they are separate from their parents. Regardless of the situation, there are two important rules for code switching. First, the speakers have to know both languages or dialects—at least well enough to follow the changes. More importantly, the switches have to be grammatical. For example, the sentence 'Tengo que do my homework' follows the 'subject+verb+object' grammar rules in both Spanish and English. One day you may be riding on a train, listening to the people next to you having a conversation. If you can understand only 50 percent of what they are saying, perhaps they are code switching—to show each other closeness, or perhaps to stop you from listening in on their conversation! What is this passage mainly about?