Nation-state refers to a country established by bourgeois revolution or national independence movement in modern times, with one or several nationalities as the main body. The nation-state is an independent political entity, and it is the leading idea and practice of modern national self-determination and autonomy in the 20th century. Different from the traditional empires or kingdoms in the 18 and 19 centuries, members of the nation-state are loyal to their "compatriots" who share a common identity and a common system. The source of identity can be traditional history, culture, language or newly created political system. Therefore, a government system composed of one nation or a country composed of several nationalities sharing the same government system are all possible combinations of nation-states.

The most important influence of nation-state lies in creating a unified national culture through national policies. The nation-state model shows that its residents are composed of one nation, United by the same ancestor, the same prophecy and many common cultures. If a country lacks such unity, it usually creates one. It promotes the unification of national languages through language policy. Establishing a unified national basic education and a relatively unified secondary education is the most effective way to popularize national languages. These schools also teach national history, which is often mixed with propaganda and legends. Especially in times of crisis, some countries still carry out such education. Sometimes, these language and cultural policies can also lead to negative effects, such as suppressing non-racial factors. Language oppression has accelerated the popularization of national languages and reduced minority languages.