I am currently learning Cantonese, bit by bit, just to survive in Hong Kong but I agree that it is a language that will be replaced by Mandarin.
As I have mentioned before at this forum, the thing you really need to study is how the Eastern and Western minds think differently (and they do in major ways). Fundamentally we see the world and how it operates in a very different way and this is the reason that we have such difficulty communicating.
If you really want to learn then get “The Geography of Thought”, by Richard Nisbett. It is like the 'Men are from Mars, Women are from Venus" for East-West relations.
The book can be found at: http://www.amazon.com/Geography-Thought-Richard-E-Nisbett/dp/1857883535/sr=1-1/qid=1172629869/ref=pd_bbs_sr_1/104-5190161-1333549?ie=UTF8&s=books