Background of Quoc Ngu

Considering that Vietnam has been an independent nation for a thousand years, Quoc ngu has a surprisingly brief history. The system was developed by Portuguese Jesuit missionaries in the 17th century. The earliest extant dictionary using quoc ngu was the Dictionarium Annamiticum Lusitanum et Latinum, published by Alexandre de Rhodes in 1651. Rhodes, who was French, relied heavily on earlier Portuguese dictionaries in compiling his work.

Quoc ngu was largely neglected until the 19th century when it was taken up by the French colonial government as a means of breaking the grip of Chinese culture and fostering Western ways of thinking. Despite its colonial background, the simplicity and ease of use of quoc ngu resulted in its gradual spread until it was finally chosen as the official Vietnamese script in the 20th century.
Features of quoc ngu
1. Diacritics are used to represent sound distinctions not covered by the Roman or Latin alphabet. This is not unusual. Although it is used around the world, the Roman alphabet is actually inadequate to represent even the languages of Europe. Some diacritics in Vietnamese:
The letter (not strictly speaking a diacritic) represents an ingressive 'd' sound, which means that the breath is not exploded outwards, it is held inwards, so to speak. (The Vietnamese /b/ sound is also ingressive, which gives it a peculiar auditory impression quite different from English /b/).
 , and are the unrounded versions of and respectively. These unrounded vowel sounds are not found in most European languages.
For short vowels, represents short while represents short .
The letters and represent the distinction between [ ] and [ ] in IPA symbols (mid-open and mid-close front unrounded vowels respectively). Similarly, and represent the difference between [ ] and [ ] (mid-open and mid-close back rounded vowels respectively). The result is a neat and regular distinction, better than that in some European languages (See this article for French and this article for German).
Since European languages do not have tones, diacritics were introduced to represent these ( , , , , , and ).
While helping achieve a regular and predictable spelling, diacritics are cumbersome to write and cause problems on computers and browsers. International Roman-letter character sets (such as ASCII) are unable to accommodate all the Vietnamese forms, so special encodings have had to be devised. At present there are several mutually incompatible systems of encoding, causing confusion and technical difficulties on the Internet. Recent