I can't really comment on the language used, except to say that it sounds marvelous!
I thought Cantonese was mainly spoken in Hong Kong and a handful of other regions, and not that wide spread.
Anyway, I saw the film yesterday and was impressed. I highly recommended it (not just for Sinophiles). My only quibble is that it failed to find a suitable pace. The visuals are stunning. Just my 2CNY :-)