Chapter 4 discusses the difference between languages and dialects, and it pays attention to the way language is used to convey a particular ideology.

The difference between a language and a dialect is based on political rather than linguistic criteria. The most powerful variety is called a language, whereas the other varieties are called dialects. Moreover, varieties change over time and place. Even though standard varieties are clearly distinct, dialects slowly develop from one language into another one.

In Europe, languages are generally clearly separated from each other, as they reflect nation-states. This is less the case on other continents, which have more languages. As a result of political decisions, language varieties can be made different or more similar to one another. The names of languages, places, and people can be highly political as well.

Languages can be made different when changing their spelling, vocabulary, and grammar. Spelling and script are the most visible aspects of language policy, but grammar and vocabulary can serve political purposes too. They can be used to signify social class, gender, and race. Yet attempts to deliberately change a language are often rejected by language users.