When Guo Chunquan speaks to his grandsons, he refuses to use Mandarin, the language spoken across nearly all of China. He wants to make sure they also learn the dialect he grew up speaking, Samatao, even if they can speak it only with each other.
Though Samatao was once dominant in several small towns in China's southern province of Yunnan, today there are only a handful of people who can still speak it, nearly all of them over the age of 40. Unless Mr. Guo's grandsons can persuade their friends to learn it, the language will likely die out completely in the coming years.
There are no more schools that teach Samatao, and even in Mr. Guo's hometown of Zijun - the village where the language was born - it's heard only when the 60-year-old former Communist Party official gathers with his fellow retirees for their daily game of mahjong. The language of business in the small farmers' market at the heart of this tiny village, and all of those around it, is Putonghua, or standard Mandarin Chinese.
"Fifty years ago, people in Zijun would curse you if you dared to speak Mandarin to them," said Mr. Guo, sitting in the local Communist Party headquarters under propaganda slogans printed in Mandarin. "Why didn't we protect our mother language?"
Five decades after China made the promotion of Mandarin an official government policy, Samatao is one of 88 languages in China that are listed as endangered by the United Nations Educational, Scientific and Cultural Organization. But as China began its once-a-decade census this week - an effort to count and learn more about a population estimated upward of 1.3 billion people - nowhere on the 18-question short form or 45-question long form of the survey are citizens asked what language they consider their native tongue.
Also unasked on the census is whether the respondents practise any religion, another sensitive topic in a state ruled by the officially atheist Communist Party, but where Buddhism, Taoism, Christianity and Islam are all gaining adherents despite government efforts to curb the spread of "foreign" beliefs.
Fang Nailin, the vice-director of the census, said there was some debate about whether or not to include a question about language on the survey, but in the end the government decided the information was "not that important." Given that the census asks respondents about everything from their level of education to the number of rooms they have in their house, the omission puzzled some of those concerned about China's disappearing languages.
"They didn't ask about something that we really need to know, but they did ask how many houses people have and how many rooms. I don't know why that is," said Chen Xizhou, an expert on minority languages at the Yunnan Institute for Nationalities.
Though Mandarin, which Beijing sees as a national-unity tool, dominates in schools and is the only language heard on national television and radio stations, China has hundreds of dialects and languages that are still in use, many of which are mutually unintelligible. A large percentage of Chinese speak two languages - standard Mandarin in public situations, and local dialect when with their family.
A series of peaceful protests in October by Tibetan students angry at being forced to study in Mandarin illustrated again how sensitive an issue language is in China. The southeastern province of Guangdong has also seen a series of rare public demonstrations in recent months against a perceived government effort to reduce the local use of Cantonese.
Samatao, which is also referred to as Zijun dialect, is a branch of Yi, a language from the Tibeto-Burman tree that has its own written script. Yi has two million speakers and seems in no danger of perishing.
Samatao, however, is regarded by UNESCO as "critically endangered," with just 100 known speakers left as of a decade ago. Though there won't be any census data to confirm it, the number is certainly lower now.
Bi Jiagui, a 70-year-old middle-school teacher, said Samatao - like many other minority tongues in China - is a victim of both state promotion of Mandarin and sheer demographics as large numbers of Mandarin-speaking Han Chinese settled in parts of the country that were once dominated by ethnic minorities.
"The people living around Zijun now are all from the Han majority, so we had to speak with them in Mandarin. The other thing that happened was the education system. All the schools started teaching in Mandarin," Mr. Bi said, speaking Mandarin himself. The last classes teaching Samatao ended in 2003, he said, when Zijun's elementary school was shut and children were forced to start attending school in the nearby city of Kunming.
Mr. Bi said he made an effort to teach his own children Samatao, but failed. They're grown now, and live their lives entirely in Mandarin.