I disagree, but I'd like to add that just like everywhere else in the world, the younger generations have a higher average level of education and linguistic ski

I disagree, but I'd like to add that just like everywhere else in the world, the younger generations have a higher average level of education and linguistic skill, thus being better at both second and third languages than the previous generations. Mandarin words are also adopted in local languages to fill gaps by the younger generations, just like English words are often put to use in the west. Not as fully incorporated loan-words, but just as a Mandarin word randomly injected into a foreign language sentence (Those speaking Cantonese use English words instead). However, the native tongue of the younger generations is not Mandarin, at least not in any of the areas I have knowledge of. Source: Married to a native Shanghainese (who is in the 20-30 range) who spend half her life in Hong Kong, and thus spoke Cantonese, Shanghainese, Mandarin and English fluently out of necessity (more western languages have been added to the list later on).