I recently went and saw The Grandmaster, and one of the more interesting subtleties I noticed was that the Northerners were speaking in Mandarin while the South

I recently went and saw The Grandmaster, and one of the more interesting subtleties I noticed was that the Northerners were speaking in Mandarin while the Southerners were speaking in Cantonese. That isn't noted in subtitles anywhere. (I'm ethnically Chinese, grew up in a household speaking Cantonese, and took some lessons for Mandarin.)