National identity is a complex and contentious issue. One of the most basic components is the Vietnamese language. Many Vietnamese are tremendously proud of their language and its complexities. People particularly enjoy the rich opportunities for plays on words that come from its tonal nature and value the ability to appropriately use the countless number of adages and proverbs enshrined in the language. Vietnamese also have an attachment to their natural world. The expression "Vietnamese land" (dat Viet) , with its defining metaphors of mountains and rivers, encapsulates the notion that Vietnamese society and culture have an organic relationship to their environment. Another important component of national identity is the set of distinctive customs such as weddings, funerals, and ancestor worship that Vietnamese perform. These are subject to a great deal of regional and historical variation, but there is a perceived core that many regard as uniquely Vietnamese, especially the worship of matrilineal ancestors by families. Vietnamese food, with its ingredients and styles of preparation distinct from both China and other Southeast Asian nations, also defines the country and its people.
Contemporary national identity's contentiousness derives from the forced unification of the country in 1975. Prior to this, the northern sense of national identity was defined through its commitment to socialism and the creation of a new, revolutionary society. This identity had its own official history that celebrated such heroes as Ho Chi Minh and others who fought against colonialism, but rejected many historical figures associated with the colonial regime, the Nguyen dynasty, and what it regarded as the prerevolutionary feudal order. South Vietnamese national identity rejected Communism and celebrated a different set of historical figures, particularly those that had played a role in the Nguyen dynasty's founding and preservation. After unification, the government suppressed this history and its heroes. The northern definition of national identity dominates, but there remains alternate understandings among many residents in the southern and central regions.