I had the privelege of studying Vietnamese for 2 semesters at my university. During the course of my studies, I had to learn the system of writing Vietnamese known as Quốc Ngữ. Seeing as how the older writing system (Chữ Nôm), which employed Chinese characters, was used up until the beginning of the 20th century, I could not understand why the spelling of such a new system was so irregular. Recently, however, I began reading An Introduction to Vietnamese Literature (Duran and Huan, 1985), which contains a section on the evolution of the quoc ngu system.
Quốc Ngữ was put together by Spanish, Italian and Portuguese missionaries, using spelling rules they were already familiar with. G and gh for example. In Italian, g is pronounced hard unless it is gi or ge, in which case it makes a j sound; Ghe and ghi are used to make a hard g in those cases. This spelling carried over to Vietnamese spelling rules; gi now makes a z or y sound, depending on the dialect, while gh is used for a hard g sound before i and e, e.g. ghế, ghi.
This and many other irregularities were taken notice of by Vietnamese and French linguists early on in the adoption of Quốc Ngữ. Several times reforms were put forward for consideration, but all of them came to nothing. For example, in 1902, at the First International Congress of Far Eastern Studies in Hanoi, Vietnam’s first Transliteration Board suggested the following improvments:
- g should be kept for the series ga, ge, go, gó, gu, gú; gi should be replaced by j;
- the k sound should always be spelled k, in order to avoid having ca and co on the one hand and ke and ki on the other.
- â, the sound of which is close to o, should be replaced by hooked a;
- y should be substituted for i in ly, ky, my, etc.;
- ch should be written as č or c, as h should be reserved for aspiration in kh, th, etc. e.g. co for cho (“market”), khac for khach (“guest, foreigner”);
- d should be replaced by z;
- n should be used in place of nh (ban for banh [“cake, bread”]);
- w should be used to denote the semi-vowel (kwa rather than qua [“to pass”]);
- s should signify a retroflex s;
- x, the sound of which is close to that of the palatal sibilant, should be replaced by ç.
All of the changes made sense phonemically (provided that the change for n occurred only word finally), but none of them caught on. Supposedly force of habit, along with the difficulty of altering fonts for printing, were the cause.
I wonder how much Vietnamese has changed since then. I also wonder how the petrification of quốc ngữ irregularities may have affected modern Vietnamese; spelling, when internalized by a native speaker, can affect pronunciation (sometimes by overcorrection). My teacher was adamant that I pronounce khach with a ch sound at the end.
The book is on google here.