A Financial Times story by Christian Oliver and Kang Buseong describes the problems of linguistic integration in Korea:
The North and South Korean languages have grown apart so severely over 65 years of division that both countries have agreed to collaborate on a joint dictionary to stem the growing confusions. North Korea’s language is filled with ideological terminology while South Korean is awash with foreign words.
Thirsty South Koreans happily order a “juice” but North Koreans ask for “danmul” – literally “sweet water” – a word that is greeted in Seoul with either bemusement or derision depending on how forgiving the waitress is. …
Han Yong-un, South Korea’s head of the dictionary project … says the North has agreed to distribute the completed dictionary to libraries and universities. South Korea’s lexicographers, sponsored by Seoul’s unification ministry, plan to issue shorter volumes for professional spheres such as medicine and technology.
In the simplest cases, problems derive from old regional differences, with North and South Koreans using different words for “geese” and “wolves”.
South Koreans import foreign words whereas North Koreans create indigenous ones. For example, shoppers in Seoul buying tights will simply ask for “stocking” whereas North Koreans have a pure Korean word “salyangmal” meaning “skin-sock”. Mascara in North Korea is “nunsseobmeok” or “eyelash-ink”.
For the South Korean dictionary compilers, the toughest words are political. Words such as “comrade” are far more loaded in North Korea, thanks to decades of Soviet influence. Most difficult is the word “juche” which is the North Korean state ideology, often translated as self-sufficiency. To South Koreans the word simply means “subject”.
I hadn’t realized there were such significant differences, though of course it makes sense. (Thanks, IndigoJones!)