Pronunciation of Korean Words    

Korea introduced a new Romanization system in the late 1990’s (replacing the McCune-Reischauer system), in part as a response to what was perceived as incorrect pronunciation of Korean words. The new system exempted family and given names from the change for a period of time.

The new romanisation transformed the spelling/pronunciation in English of the following letters in particular, from:  
ㅂ  (was P now B)   Example: the city of Pusan became Busan
ㄷ  (was T now D)     Example: Tongdaemun Market became Dongdaemun Market
ㅈ  (was CH now J)   Example:  Cheju Island became Jeju Island
ㄱ  (was K now G).   Example: Kimpo Airport became Gimpo Airport

However, some information sources still refer to the old spelling because it was not possible to go back and change everything (i.e. Internet sources), because Korean-only speakers never thought of making the change (as can be seen on letterhead and business cards) or refused to implement the new system.

The Romanization used varies from one government or government agency to the next. For example, most government sites give one of the country’s provinces (경상도) as Gyeongsang-do, while KoRail (Korean Railroad) spells it Kyoungsang-do. Koreans and most long-time foreign residents (especially those living in the Daegu/Taegu and Busan/Pusan areas) know that both designations refer to the same place, but new arrivals and visitors often think they are two different places.

Adding to the confusion are some family names that Koreans have decided to spell a particular way in English even though that spelling does not reflect the pronunciation of the name.
For example:
Lee, Rhee, Yee  or Yi are the Romanised versions of 이 pronounced “Ee” in Korean
Park is the Romanised version of  박 pronounced Pahk in Korean
Roh is the Romanised version of 노  pronounced No in Korean
Choi  is pronounced Choy in English, although   최 is  more like Chwae in Korean
Chung or Jung is written 정 in Korean, and pronounced Chong
Paek,Baek,even Back or the Romanized versions of 백 which is pronounced in between P/B.

For those who apply to new romanization to Family names, here is what you get:
Kim becomes Gim
Pak/Park becomes Bak
Paek is Baek
etc.