Totally distinct from Chinese, the languages of minority groups such as Tibetans, Uighurs and Mongolians are officially recognized and taught in schools. Important documents are translated into major minority tongues and four of them -- Tibetan, Mongolian, Uighur and Zhuang -- appear on Chinese bank notes.
Chinese dialects are based on the same system of writing. That means that Cantonese speakers in Hong Kong can enjoy subtitled Mandarin movies and Mandarin-speakers can order off Chinese menus in the far west of the country.
Rising incomes, greater travel freedom and the spread of education are also helping to break down linguistic barriers. Yet no one is predicting that they'll dissolve entirely -- or soon.
"Many parts of China are heading for a situation of what linguists call diglossia, where there is one 'high' or public language ... and one 'low' or local language that is used among friends and family," said Stevan Harrell, an expert on Chinese languages at the University of Washington.
Use of dialects may even be strengthening in some areas with strong local identities, sometimes for economic reasons. In Guangzhou (that's Mandarin for the great southern city of Canton), broadcasters are allowed to speak Cantonese to compete with the nearby Hong Kong stations.
In places like Guangzhou and Shanghai, prevalence of the local dialect helps exclude outsiders from social networks that are key to securing good jobs and entry to better schools. Outsiders say it smacks of bigotry.
"If you want to find a good job and be a success in Shanghai, you have to speak Shanghainese. Even if you do, they can pick you out by your accent and discriminate against you," said Steven Li, an accounting student flying home to the western city of Chongqing.
Preservation, not exclusion, was the purpose of Tom and Jerry in dialect, said Zhang, the producer.
"You've got Shanghainese kids who can't even speak Shanghainese," he said. "I have friends who've moved to Shanghai and want to learn the language to better integrate into local society.
"Isn't watching TV easier than studying textbooks?"
Zhang cites semi-legal Shanghainese broadcasting that pops up on local radio as evidence of continued demand for dialect programming. For now, Tom and Jerry will continue in Shanghainese on video, along with other versions in close to a dozen dialects.
Oddy enough, Tom and Jerry didn't speak in the original cartoons, so the dialect versions give them voices they never had.
