BEIJING, Aug 20 (AP) -- About 70 percent of China's estimated 200 million migrant workers have difficulty speaking the national language, Mandarin, though most are required to use it in their jobs, state media reported Monday.

Most prefer to speak in one of the country's numerous local dialects, and about 70 percent of them found it hard to speak Mandarin, the official Xinhua News Agency said, citing a Ministry of Education report on the country's language situation last year.

China has, at any one time, an estimated 200 million workers in its cities who have migrated from rural areas, according to official statistics.

Mandarin Chinese is the country's national language, also called "putonghua." All Chinese dialects share the same written language, but pronunciation of identical words differs from area to area, especially between northern and southern China.

Less than three percent of the workers had access to language training, though 80 percent were required to speak Mandarin by their employers, Xinhua said. Many of those required to use Mandarin work in the restaurant industry, which employs many rural workers.

Local governments and employers should offer Mandarin courses to migrant workers to help them better adapt to urban life, Ministry of Education language administration official Li Yuming was quoted as saying.