That's very interesting. However I am not sure whether being middle/upper class has any association with being able to speak english. Frankly I don't think there is a class distinction in China (despite an economic one maybe).

I would like to point out if helpful that in China our education of the English language is much more geared towards reading rather than speaking. Students are generally equipped with enough to read and understand given adequate time but probably not speaking. However regional difference also may exist (first tier cities vs second, third etc). I used to feel ashamed about our english level in east asia in general. But then again now I think about people in the anglosphere where French and Spanish are largely taught but no one would expect a large proportion will be able to converse in them :)