There are many reasons that languages change. One reason is that technology changes. We use new words for new types of technology. Thirty years ago, we only used the word mouse in English go describe an animal. Today, the word mouse also means the object you use to contro a computer. Another important reason for language change is communication between different countries and cultures. For instance, English uses word like sugar from Arabic, shampoo from Hindi and yoghurt from Turkish. Languages also change because young people create their own way of talking thatis different from their parants. Teenagers often use new slang - informal words and pnrases - to talk to their friends. Some slang gets forgotten, but other slang words become part of normal, everyday language. Words like bus and rock music started as slan, but now they are in the dictionary.