I think you can take it as a synonym as Chinese, but it’s for spoken language. It’s the offical spoken language in China, also called Putonghua.
The speed sign reads: School Zone Ahead, Please Reduce Speed
(Speed limit: 30 km per hr)
more pictures here (WARNING: graphical and disturbing photos)
http://cache.tianya.cn/publicforum/content/free/1/1239384.shtml