Did the Vietnamese people have their own system of writing before their cultural contact with China? This is a question which archaeology and linguistics have also so far been unable to answer.
During the centuries of Chinese occupation, Chinese was in Vietnam, as Latin in medieval France, the only written language, used in official documents as well as literary works. The Chinese characters were called "Chu Nho", which literally means "the scholars' script". Although written in the purest tradition of Chinese calligraphy, the Chinese characters received, however, a distinctly Vietnamese pronunciation, which enriched the Vietnamese spoken language with newly-coined Sino-Vietnamese words. A great number of Chinese words. mostly philosophical terms, were thus adopted.
The first stage of Vietnam's linguistic or rather scriptural "liberation" from China began in the mid-13th century with the development of a new system of writing which, although still based on the Chinese characters, was specifically Vietnamese, the "Chu Nom" (literally "the vulgar system of writing "). Under this system, each Vietnamese word was transcribed by the combination of two Chinese ideograms, one used for phonetization purposes, the other to indicate the meaning.
The knowledge of Chinese was still necessary to understand "Chu Nom". Furthermore, there were no fixed and strict rules in the combination of Chinese characters, which often led to several different possible interpretations of the same word.
In spite of all these shortcomings, during six centuries, the "Chu Nom" was to be used as a literary language alongside the "Chu Nho". Han Thuyen, a mandarin and poet of the 13th century was a pioneer in its literary use.
A true linguistic revolution took place in the 17th century with the "romanisation" of the Vietnamese language. The name of the French Jesuit missionary Alexandre de Rhodes, from Avignon, is generally associated with the invention of " Quoc Ngu " (literally "national script") using the Roman alphabet.
The first printed work in "quoc ngu" was Alexandre de Rhodes' Cathechismus published in Rome in 1649. But the development of the new script was in fact a collective undertaking which started in the early 16th century. Several generations of Catholic missionaries, Spanish, Portuguese, French and Italian, took part in this undertaking. Although not often mentioned, the contribution of Vietnamese scholars, mostly Catholic catechists, was certainly not negligible.
The "quoc ngu" was codified in the late 17th century but it was not until the early part of the 20th century that it was definitely adopted and gradually superseded the "chu nho" and "chu nom".