SEOUL — If North Korea and South Korea ever reunite, they’ll have to address their language barrier.

In an effort to unify the language, researchers on both sides have started working on a dictionary. But who knows when it'll be done. Every time relations between the countries chill, the whole project stalls because the two sides can't meet with each other.

North and South Korea share a writing system, and for the most part, citizens of either country can understand one another. But in the 70-plus years since the countries split, the “Korean” spoken on both sides has started to drift further apart.

"North Korea's national language system is still heavily influenced by Kim II-sung's juche philosophy. Most of the foreign words have been converted into traditional Korean language, " said Professor Hong Jong-seon, Chairman of United Korean Dictionary Committee. "South Koreans, however, tend to be very open to foreign culture and use many Western words in their everyday life."

Because of that, North Koreans who defect often have trouble navigating life in South Korea. Political concepts that don’t exist in North Korea can be confusing — and even basic words like “lunchbox." Friendly North Korean phrases about food can also inadvertently offend South Koreans.

VICE News visited a professor who's leading the project to find out what it’s like to make a dictionary for a unified country that doesn’t exist yet.