Joo Yeon-ah did not realise how hard it would be to settle in South Korea. The 45-year-old defector says she was prepared for the dangerous journey out of North Korea, and the unfamiliarity of everyday devices such as mobile phones and cash machines. But what she wasn't expecting was a communication barrier with people who spoke the same language. "I didn't understand [what people were saying]," said Joo, who has lived in Seoul since 2009. "Everything is so different in South Korea, but I thought at least our language would be the same." What she discovered is that after more than 60 years of division, different forms of the Korean language have evolved, with the South incorporating many words from English. For example, North Koreans express anxiety by saying in Korean, "My head hurts", while South Koreans use the English word stress, which they pronounce suh-tu-reh-suh . Now scholars from both sides of the peninsula are collaborating on a project funded by the South Korean government to create a unified Korean language dictionary. Known as Gyeoremal-kunsajeon (the Korean People's Comprehensive Dictionary), the initiative is intended to bridge the linguistic divide in a future where the two Koreas are reunified. "Time has passed and the language has evolved," said project director Han Yong-un. "Those changes will continue, but when reunification happens, we need to be ready." After the 1950-53 Korean war, South Korea opened its economy and society to outside influences while the North resisted any foreign incursions, particularly from the English language which the Pyongyang regime associates with American imperialism. Rather than borrowing new words from English, North Korea has come up with home-grown substitutes. For example, when watching or playing football, South Koreans simply use the English expression "penalty kick", while in the North they use a Korean term that translates as "11-metre punishment". South Koreans use the English word "juice", while North Koreans use a term that means "sweet fruit water" in translation. Han says that in daily life, the languages are "about two-thirds" the same. But in business or professional settings these differences become more pronounced. "We could end up with a situation where doctors are in an operating room performing surgery and aren't able to understand each other," said Han. The project's hope is that in a reunified Korea, people will be able to consult the dictionary when there is confusion over unfamiliar words, and to solve the misunderstandings that may arise. Han says he and his South Korean colleagues have completed comprehensive definitions of more than 20,000 words. The completed dictionary is set to contain more than 300,000 words.