[Jongseong]

Actually, they do teach Chinese characters in school in North Korea; it is a common misconception that they don't. They teach 3,000 characters, which is numerically even more than the 1,800 characters taught in South Korea in school. But as you said, in North Korea you don't even see the very limited usage of Chinese characters in newspapers that you see in South Korea, so it is not much beyond a subject you learn in school. You could say the same about the situation in South Korea, though, since the usage of Chinese characters is really, really limited, mostly to certain newspapers.

The notion that North Koreans say 얼음보숭이 (ŏrumbosung'i) for "ice cream" is a bit of a myth. The authorities in North Korea did indeed introduce this word as a part of a linguistic purification effort, but it doesn't really seem to have caught on. A 1962 North Korean dictionary only has 아이스크림 (aisŭk'ŭrim) "ice cream", just as in South Korea. A 1981 edition of another dictionary and a 1984 encyclopedia introduce 얼음보숭이 (ŏrumbosung'i), but the official dictionary that appeared in 1992 again has 아이스크림 (aisŭk'ŭrim) "ice cream" and not 얼음보숭이 (ŏrumbosung'i). The 1992 dictionary also has 에스키모 (esŭk'imo) "eskimo", which in North Korea is a popular everyday word for "ice cream" which comes from a name of a brand that was popular there.

You have plenty of examples of South Korean language authorities introducing "purified" (often pure Korean) words to replace loanwords, which don't necessarily catch on. For "stapler", the official South Korean dictionary has the pure Korean translation 찍개 (jjikgae), for instance. But I have never seen this term in the wild—instead, people say 스테이플러 (seuteipeulleo) "stapler", or more commonly, 호치키스 (hochikiseu) "Hotchkiss". There is a limit to how much official language policy can dictate actual usage, whether it is in North or South Korea.

[hcolomb]

Well fancy that-- Everything I knew was a lie!

Would you happen to know anything about the usage of konglish in North Korea then, as in words besides 아이스크림 or 에스키모? Is it more frequent near the border or just as spread through as it is in SK?

[Jongseong]

Are you talking about loanwords from English in the Korean used in North Korea? Korean was already borrowing words from English decades before the division of the peninsula, as you can see in writings from the Japanese colonial period. So North Korea inherited a lot of these same loanwords. It has nothing to do with South Korean influence, if that's what you're suggesting, as the language communities of the North and South have been effectively cut off from each other since the war.

However, there are often differences in the spelling of such loanwords between the North and the South. So you have 프로그람 (p'ŭrogŭram) in the North but 프로그램 (p'ŭrogŭraem) in the South for "programme", 텔레비죤 (t'ellebijyon) in the North but 텔레비전 (t'ellebijŏn) in the South for "television", and 미싸일 (missail) in the North but 미사일 (misail) in the South for "missile". This is due to the fact that the standardized spelling of loanwords (a problematic and much debated area of Korean orthography) was frequently reformed in South Korea, and probably in the North as well, so the principles of spelling have turned out quite differently between the two. Also, as North Korea uses a lot of loanwords from Russian, even loanwords originally from English tend to be absorbed in the Russian pronunciation, such as 땅크 (ttangk'ŭ) for "tank" or 뜨락또르 (ttŭrakttorŭ) for "tractor" as opposed to SK 탱크 (t'aengk'ŭ) or 트랙터 (t'ŭraekt'ŏ) which is closer to the English pronunciation.

The official language policy in both the North and the South tends to discourage loanwords from English, but it seems a bit more successful in the North, especially when it comes to post-1945 loanwords. If you only focus on the differences between the North and the South, then you see many cases where North Korea uses native Korean words whereas South Korea uses loanwords from English. But you can't extrapolate from that and conclude that North Korea doesn't use loanwords from English at all. This would be a misconception, just like the false notion that North Korea doesn't use Sino-Korean words.