“Yes, you have a language, but if you want mass literacy, this thing is a disaster,” said Mr. Moser, who is the academic director at CET, a Chinese language program in Beijing, has a Ph.D. in psycholinguistics and Chinese, and has lived in China for more than 30 years. “The written symbols are fantastically hard to master.”

To make it easier to learn thousands of characters that do not correspond to the sound of words and must be memorized, a Romanization system called Pinyin was introduced. But the reformers’ most ambitious plan — abolishing the characters altogether — was never carried out.

Image David Moser, the author of “A Billion Voices.” Credit... Zuo Cui

“You have to feel sorry for Chinese school kids,” said Mr. Moser, who likened learning Chinese to a “cognitive traffic jam.” “In the first years of their basic education, they must study and master two script systems, one foreign, the other familiar but devilishly hard to write and unreasonably time-consuming to memorize.”

In Mr. Moser’s book, the efforts to define a national language run parallel with the decades-long fighting among warlords; the Kuomintang, or Nationalists; and the eventually victorious Communists to control and redefine the Chinese nation. As he described it:

“The first part is a historical documentation of the struggle for a unified language of some kind. That’s why I structured it as a battle to win China, since the warlords and Nationalists were also fighting linguistic battles. “The second part is after Mao Zedong came to power, how they came to enact this policy under a unified government. That’s an ongoing story, the end of which is not seen. There are still 300 to 400 million people who cannot speak or read Putonghua easily. “And the third part is the messy linguistic explanations I have to throw in, because I can’t assume the reader knows anything about Chinese.”

A major question he addressed is why the creation of a national language in China was so much more difficult than in, say, European nations.

“The literary tradition began very much as an elite activity that only scholars could take part in. Very quickly in Greece and Rome there was a democratizing effort and the Greeks tried to publish their work in an oral language. That never happened in China. China has always had this problem with getting its language from basically a written form, a dead written form, to a living speech.”

China, much like the African continent, had an enormous array of languages and dialects. But the Chinese government mostly calls them dialects rather than languages, even if some are mutually unintelligible. Mr. Moser explained the political reasoning behind this:

“The Chinese situation is exactly the same as other places on earth — Africa, Europe, too. But Chinese wanted to unify the nation. It’s a matter of political realities. The Roman Empire broke up into different countries. Had China broken up, suppose Mao had not unified it, we would be looking at something like Europe — with a ‘Guangdonia’ and ‘Shandonia’ or ‘Sichuania’ [derived from Guangdong, Shandong and Sichuan Provinces] with their own language and dialects. “The difference is that China considers this country a unified political and cultural entity, and therefore, ‘We’re going to call these things dialects.’ You can’t call them languages, because that would imply they are different regions.”

Hundreds of millions of people in China and elsewhere are learning Chinese. But without a phonetic system to guide pronunciation, it is famously difficult.

“For languages that use alphabets, reading, writing and speaking form a ‘virtuous circle,’ making up one composite skill. In Chinese, the circle is broken and none reinforce the other. In English, the spelling of the word ‘dragon’ conveys the sound of the word, and the sound of the word is enough for the learner to quickly remember how to write it. In Chinese, the traditional character for ‘dragon,’ 龍, sits silent and imposing on the page and can only be remembered through countless hours of repetitive practice.

Although young learners in China have little choice, outside the country, among the Chinese diaspora communities, the pull of English is strong. Mr. Moser laid out some of the consequences:

“Parents don’t like to hear this, but kids aren’t stupid and they vote with their time and interest and say, you know, I’m going to skip the difficult Chinese and go with the fun English stuff. As long as I can remember, parents have been tearing their hair out: ‘How can I get my kids to read Chinese books?’ The issue is the characters, and people don’t want to admit that, but it’s true. It’s a serious impediment. “And it’s a serious impediment to Chinese soft power. Because if you want your books to win prizes, your films to be watched, you need people to be able to delve directly in. And with the characters there it lowers participation drastically.”

What is saving Chinese now, he said, is digitization: