They are absent from some analyses and romanization systems.
Other syllables are modernized as follows (see also Japanese romanization systems).
It replaced the Nanjing-based romanization systems that was common until the late 19th century.
A variant of it was used as the official romanization system in South Korea from 1984 to 2000.
Any romanization system has to make a number of decisions which are dependent on its intended field of application.
But Cantonese, with double the number of tones, has four or five competing romanization systems.
The official romanization systems in the Republic of China have been:
It replaced the Nanjing-based romanization systems that had been common until late in the 19th century.
While not being a form of the Latin alphabet, it still functions like a romanization system in modern use.
The differences between the three romanization systems are shown in the following table:
