I can recommend the book Language Attitudes and Identities in Multilingual China if you find a copy. I got it from the library and have read the first 2 chapters and have already learned so much from it!

I was also able to get a copy of the paywalled article, but it wasn't quite as informative as I'd hoped. It was more of a dry summary of survey results than explanation/context/hypothesis. However, in that same issue of the journal (Journal of Asian Pacific Communication volume 26, issue 1) there were several other interesting articles.