The Vietnamese language belongs to a language group which was established a long time ago in East Asia. Changes in material conditions over many centuries and the increasing demands of cultural life have influenced the Vietnamese language.
While adopting many elements of the Chinese language, the Vietnamese people changed many Chinese words, gradually creating Han-Viet (Chinese-Vietnamese) which incorporated purely Vietnamese words. "Vietnamization" not only applied to the Chinese language, but also to French and other language groups, creating a diverse vocabulary for the Vietnamese language.
When the multi-ethnic Vietnamese nation was taking shape, a great monarchy was established in the North, and it began a southward expansion. The Vietnamese nation underwent thousands of years of Northern domination. This was why Chinese was used for a long time as the official written language. Local mandarins of various levels were allowed to sit for examinations in the Northern Court (China), and were recruited into the administrative machinery of foreign invaders.

Based on Chinese characters, the Vietnamese worked out a unique writing system of their own called Chu Nom. In Chu Nom, two Chinese characters were usually combined, one of which indicated the meaning of the Vietnamese word, while the other indicated pronunciation. Chu Nom was welcomed and widely used by the masses in their daily life, as well as in transcribing their national history and literature. According to researchers, Chu Nom probably originated around the end of the Northern domination period and early in the 10th century (the independence period). The oldest evidence of Chu Nom currently available is a stele in the Bao An Pagoda in Yen Lang, Vinh Phu province, dating back to 1209 AD (Ly Dynasty). It was not until the 13th century under the Tarn dynasty that Chu Nom was systematized and used in literature.

Nguyen Thuyen (alias Han Thuyen) and Nguyen Si Co wrote poems in Chu Nom. Ho Quy Ly (1400 AD) made Chinese textbooks which translated the Vietnamese language using the Chu Nom writing system. He also used Chu Nom to write royal proclamations and ordinances. In the 15th century, Nguyen Trai, a national hero, used Chu Nom to write 250 poems in Quoc Am Thi Tap (Collection of Poems in the National Language). The Chu Nom literature continued to be developed from the 16th century onwards and totally dominated national literary circles. Ba Huyen Thanh Quan (the wife of the Chief of Thanh Quan district), Cao Ba Quat and Kieu Story of Nguyen Du, and the translation of Chinh Phu Ngam (Lament of a Wife Whose Husband has Gone to War) by Doan Thi Diem were quite noteworthy poems.

In conjunction with the development of the nation, the Vietnamese language was constantly developed and improved. Around the 17th century, western missionaries came to Vietnam and learned Vietnamese in order to disseminate Catholicism. They developed a romanced script to represent the Quoc Ngu (meaning national language) in order to translate prayer books and catechisms. A number of Portuguese and Italian missionaries used Quoc Ngu to compile catechisms and Portuguese-Vietnamese and Vietnamese-Portuguese dictionaries. Based on these works, Alexandre de Rhodes, a French Jesuit missionary, published the Vietnamese Portuguese-Latin dictionary which was a fundamental catechism in Rome from 1649-1651. After Alexandre de Rhodes, Quoc Ngu was further improved by foreign missionaries and Vietnamese scholars.

In 1867, some colonial schools began to teach Quoc Ngu. It was not until early in the 20th century that Quoc Ngu became widely used in the local primary educational system. The introduction of Quoc Ngu constituted a new step in the development of the Vietnamese language. While romanization received a reserved welcome in other Asian countries, it recorded extraordinary success in Vietnam, creating favorable conditions for cultural and intellectual development.