Only about half of China's population can speak the national language, Mandarin, according to the state news agency Xinhua.
There are hundreds of dialects among China's 1.3bn people
More men speak Mandarin than women, and more urbanites speak the language than those in rural areas, Xinhua said.
For many years now, the government has tried to increase the use of Mandarin, to promote social cohesion.
But China has hundreds of dialects, some of which - such as Cantonese and Hokkien - have strong regional support.
In a survey of 500,000 people around the country, the Ministry of Education found that only 53% of people could "effectively communicate" in Mandarin, Xinhua reported.
In urban areas, 66% of residents spoke fluent Mandarin, while in rural areas only 45% of those surveyed could "effectively communicate orally" in the language, said Xinhua.
Only 31% of those aged between 60 and 69 were able to speak it, compared to 70% of people aged between 15 and 29, the survey found.
Vice-Minister of Education Zhao Qinping has recently announced that the government will focus on promoting Mandarin in the countryside this year, Xinhua said.
"Lessons in [Mandarin] will be included in skills training for farmers wanting to migrate to cities to find work," it said.