Without an understanding of concepts like private property, commercial transactions and choice, how do you explain to a communist about renting office space in the US?
The question sounds like the start of a joke in search of a punchline, but this conundrum faced Tong Kim during his 27 years as a senior translator with the US State Department. He has been party to some of the most sensitive negotiations between the US and communist North Korea.
The difficulties of his job were highlighted when representatives of the two countries discussed opening liaison offices in each other's capital. One US negotiator was tickled at the idea of a North Korean real estate agent pounding the streets of Washington in search of office space.
'Not only is there no transaction between people or between entities in North Korea, but no brokering system by real estate brokers. So this kind of stuff doesn't translate very well,' Mr Kim said. 'As an interpreter, you are meant to say what is said without adding. But once you know yourself that 'this guy will have no idea what I am talking about', you have to give them almost a lecture.'
For more than a decade, Mr Kim attended almost every high-level US-North Korea meeting. Since his retirement, he has ruffled feathers in Seoul and Washington by using his intimate knowledge of diplomatic proceedings between the two states to question the viability of an agreement reached at multilateral talks two months ago over Pyongyang's suspected nuclear weapons programme.
Mr Kim has described the statement of principles hammered out after three previously fruitless rounds as a 'linguistic minefield', full of 'hidden meanings and obfuscations'.
According to the statement - agreed by the US, the two Koreas, China, Japan and Russia - North Korea has committed itself to 'abandoning all nuclear weapons and existing nuclear programmes'. But Mr Kim says the verb pogi hada (to abandon) used in the Korean translation 'can be interpreted to mean leaving the weapons in place rather than dismantling them'.