As diplomatic incidents go, it was not a big one, but for many people in Hong Kong and southern China it felt like the latest in a long line of slights. In May, Nintendo — a Japanese toy company — launched its most recent video games of Pokémon, a franchise of creatures, and announced that the names of the creatures would henceforth be written in characters that adhere to Mandarin pronunciation, not Cantonese.

This, said the company, would help to provide unity across the greater Chinese market. On May 30, a group of demonstrators gathered outside the Japanese consulate in Hong Kong to protest.

Behind Nintendo's announcement is a bigger linguistic and political issue. As part of its broader nation-building program, the Communist Party has, since 1949, been trying to unify China under the banner of spoken Mandarin.

This linguistic homogenization is being enforced, however, just as a number of forces are pushing in the opposite direction. Technology is empowering regional languages and enhancing the centrifugal effect of migration, modernity and social change. Despite major success in literacy programs, there are still 400 million people in China who do not speak Mandarin, and some 100 million who the government says cannot read at all. The actual number is undoubtedly higher.

Part of the reason is the complexity of the Chinese script, says David Moser, author of "A Billion Voices," a new book about the Chinese language. There are few and confusing links between the form of a character and its sound. And different regions pronounce the symbols differently.

Early in the technological revolution, many thought the complexity of putting characters into computers might kill off the Chinese written language completely. But the opposite has happened as software experts have developed a fast and efficient way to write characters with a keyboard.

Although that has helped to launch 700 million Chinese people into cyberspace, it has not helped the party's efforts to synchronize written characters with Mandarin pronunciation. Last year Jackie Chan famously launched an advertisement for shampoo where he flicked his bouffy hair and exclaimed how "duang" it was. Everyone wanted to tweet it and text their friends how "duang" their own hair was, but "duang" has no character to go with it. It is one of many slang or dialect words and phrases that you can say but not write using Chinese characters. (It translates roughly as "boing" in English.)

Even if the party achieves linguistic unity under Mandarin, says Moser, it may still find social and political unity as elusive as ever.

Copyright 2013 The Economist Newspaper Limited, London. All Rights Reserved. Reprinted with permission.