English alone is perfectly sufficient in Hong Kong unless you visit some local small store ran by a single elderly owner and you cannot communicate what you need by pointing, then you may have to break out your Mandarin!

One time I was in a taxi and I thought I would make it easy for the driver and told him in Cantonese that I need to go to 港麗酒店. The guy thought for a second.. and then said in perfect English with the British Accent, "Conrad Hotel?"