that actually not correct chinese movies are in 2 dialects and i would say most movies are done in cantonese and there 2 options during making movies they doing the same parts in manadarin or dubbing movie in mandarin after so you must saw manadarin speaking version of ip man (with donnie yen) as cantonese exist as well (and i know people usually askin for cantonses version as manadarin seems unnatural)
Hongkong movies are of course mostly done in Cantonese and then dubbed, because Chinese people do not understand it (except for local people in Guangdong). Most of them can understand Putonghua (Mandarin) though. When I buy DVDs, I normally watch them in the OG, except for when my wife is also watching and wants to watch it in Putonghua.
But I guess I made a mistake. Seems like they actually kept it real by having the first mostly in Putonghua as it plays in Mainland and the second one in Cantonese as it plays in Hongkong. I bought the DVD here though, so it was in Mandarin.
Now this third movie about Ip Man is in Cantonese, but it plays in Mainland, which is still surprising to me.