A client asked me recently whether a Korean translation written for Koreans living outside Korea should be handled differently than a translation for Koreans in Korea. He mentioned that Chinese translators have told him that Chinese living outside China (such as Chinese living in the US) speak and write differently than those living in China.
The usage of Korean in Korean communities outside Korea is different than that used in the home country. Overseas Korean is often mixed with a lot more English (or whatever language it is in the local area). In addition, for various reasons, the Korean skills of Koreans living overseas are sometimes not what would be expected in Korea.
But when handling professional translation projects, we don't translate to the lowest common denominator or produce some kind of local dialect or pidgin Korean just for the local audience. The professional writing practice for Korean always remains the Seoul gold standard.
In fact, if we tried to localize to such an extent, not only would it cost more to produce multiple versions, but it would also look funny and certainly not give the correct impression.
Look at it this way... What if issues of the Wall Street Journal published in Texas were written in Texan?
For more on this and other translation services topics, check out my Korean Translation Services Buyer's Guide.