BEIJING - Born when a Qing dynasty emperor was on the throne, the man who helped invent the Pinyin writing system used for transliterating Chinese worldwide turns 109 on Tuesday. But Zhou Youguang's outspoken support for democracy means his writings are still censored by the ruling Communist party.
"After 30 years of economic reform, China still needs to take the path of democracy," Mr Zhou told AFP in an interview, his wrinkled face topped with a patch of white hair. "It's the only path. I have always believed that."
Mr Zhou is commonly known as the "father of Pinyin", a system for transliterating Chinese into the Roman alphabet introduced in the 1950s and now used by hundreds of millions of language learners in China, as well as abroad.
But in his cramped third-floor apartment in Beijing, where dog-eared books - including dozens by Mr Zhou himself - line the walls, the writer was modest about his achievements. "I don't have any feeling of pride. I don't think I've achieved very much," he said, speaking lucidly but slowly and with obvious effort. "My birthday is of no importance at all."
Born to an aristocratic family in 1906, Zhou experienced the last years of the Qing dynasty and its revolutionary overthrow, before studying at elite universities in Shanghai and Japan.
When Japan launched a full-scale invasion of China in 1937, Mr Zhou moved with his wife and two children to the central city of Chongqing, where he endured constant air raids but made contacts with leaders in the then comparatively weak Communist party.
After Japan's defeat he avoided China's civil war between the Communists and Nationalists by going to work for a Chinese bank on Wall Street, twice meeting Albert Einstein while visiting friends at Princeton.
But following the Communist victory in 1949, Mr Zhou returned home to teach economics and became a close associate of the party's number two, Zhou Enlai.
"I came back for two reasons: because I thought the country had been liberated, and had a new hope. Also, because my mother was in China," he wrote in a 2012 autobiography.
He was attracted to Mao Zedong's Communists because "at that time they promoted themselves as democrats", he wrote.
An amateur linguist who had taught himself some Esperanto, Mr Zhou was assigned in 1955 to co-chair a committee tasked with increasing literacy by reforming the Chinese language. He eventually backed a system based on one developed in the Soviet Union, using Roman letters to represent pronunciation alongside marks to indicate tone.
The proposal, named Pinyin - "putting together sounds" - is used in schools across China and has been instrumental in boosting the country's literacy rate from around 20 per cent in the 1950s to more than 90 per cent today.
Though systems for transcribing Mandarin into the Roman alphabet already existed - including Wade-Giles, produced by two British diplomats in the 19th century - Pinyin is regarded as simpler.
"With Chinese characters, you can't tell the pronunciation just by looking. So Pinyin was useful in teaching," said Luo Weidong, a professor at Beijing Language and Culture University. "Pinyin made a big contribution to the literacy movement in China."