In North Korea, they ask whether you speak "chosun-mal". In South Korea, they want to know whether you can converse in "hanguk-mal". A different name for their ostensibly common language is a measure of how far North and South Koreans have grown apart during 60 years of division. And it does not stop there.
If South Koreans ask North Koreans how they are, the instinctive answer sounds polite to Northerners but conveys a different message to Southern ears - "Mind your own business".
With such divergence, there have been fears among linguists that more decades of separation would result in two different languages or that unification would be an improbable merger of vocabularies reflecting a communist and capitalist past.
Yet recently the outlook has improved slightly.
North and South Korea have agreed to compile a joint dictionary of the Korean language and North Korea is also trying to expand studies of English and technology terms that have shaped the language in the South.
In the years following the 1950-1953 Korean War, North Korea tried to purge foreign words, especially English and Japanese expressions, from its language.
Political expressions in the isolated communist country have also become alien and incomprehensible to those in the more outward-looking South.
Inter-Korean communication in commerce invariably creates confusion - often resulting in the use of fingers - because monetary figures are quoted by South and North Koreans in the two different ways of counting in the Korean language.
The South Korean language has borrowed heavily from foreign languages, especially English.
It evolved with twists and turns beyond the imagination of those in the North, not least because the South has developed and adapted technology that does not exist on the other side of the peninsula.
South Korea is one of the most wired countries in the world. Email and SMS text messaging create new words with dizzying speed.
Words from another language such as English can be swallowed whole and then regurgitated in an abbreviated, unrecognisable form.
For example, the English term "digital camera" is called "dika" (pronounced dee-ka) in South Korea.
North Korea, by contrast, is decidedly low-tech and highly impoverished. There are no digital cameras and personal computers are hardly for the masses.
A South Korean professor who is working on the joint North-South dictionary project said he did not have any difficulty communicating with North Koreans his own age because daily expressions were the same.
Hong Yoon-pyo, a professor of linguistics at Yonsei University, said the linguistic roots of the Korean language were long and deep so there was almost no divide in the structure of the language on both sides of the peninsula.
"There is a vocabulary gap, however," Hong said. "Vocabulary can be changed by the outside world and in South Korea that mostly means the Western world and in North Korea that has mostly meant China and Russia.
"For the language used in daily life, there is not much real difference."
Hong said, two-way electronic communication in the South via emails, instant messages and SMS messages over mobile phones is a major influence and source of new terms.
"The amount of Internet connectivity makes the South an extreme case in terms of language," he said.
Hong said the dictionary project was an attempt to integrate the language as it was spoken in the two parts of the peninsula and they planned to finish the book by 2011.
In the South, people use the English term "sausage" for the food item, whereas people in the North string together two Korean terms meaning "meat" and "noodles and vegetable stuffed into a pig intestine" to mean the same thing.
North Koreans understand the English word "hamburger" but have no idea of McDonald's because no fast food chains exist in the country.
According to a 2000 survey, North Koreans could not comprehend about 8,200 key foreign words, mostly of foreign origin, used in the South Korean language.
The words included terms such as "dance music", "sports car" and "keyboard", according to a survey by a Seoul National University professor, Im Hong-pin.
I am agreed with Hong that there was not a large gap between the Korean language used in the North and South for daily life.
More North Koreans are studying English, analysts said and more North Koreans are taking a common test to measure their proficiency in American English as a second language.
The number of North Koreans taking the Test of English as a Foreign Language has risen almost five-fold in less than five years and scores for the North Koreans have also improved, the US-based Educational Testing Service said in July.
For linguist Hong, the real challenge is trying to keep up with the daily conversation of young South Koreans.
"I have much more trouble understanding my son than North Koreans," he joked.