As with any country I visit I spoke some basic local language (Hello, good morning, goodbye, thank you etc) to the guides, bus drivers and the small number of 'locals' I encountered as I believe this is the courteous and polite thing to do when visiting someone else country. They all seemed pleasant enough with me attempting their language and one guide even helped me with my pronunciations.
There was no one in my group who could speak Korean, or no one who would admit to it but the guides were very proficient in English, Mandarin and knew basic Spanish (enough to hold a basic conversation but I had to cross translate sometimes)
In reality the guides did want to improve their English by talking to you about all sorts of things. You have very little contact to anyone who is not part of the tour group or affiliated to them somewhere. You are literally guided round in groups by guides with possible 'minders' hovering around watching both you and the guide. The city areas can be very sparse and unless you are around for a public holiday there are very few people around when you are outside.