The system was created in 1937 by two Americans: George M. McCune and Edwin O. Reischauer. With a few exceptions, it does not attempt to transliterate hangul but rather to represent the phonetic pronunciation. McCune-Reischauer is widely used outside of Korea. A variant of it was used as the official romanization system in South Korea from 1984 to 2000. A third system—the Yale Romanization system, which is a transliteration system—exists, but is only used in academic literature, especially in linguistics. During the period of Russian interest in Korea at the beginning of the 20th century, attempts were also made at representing Korean in Cyrillic.
Critics of the McCune-Reischauer system claim that casual users of the system omit the breves over the o for 어 and the u for 으, because typing o or u without the breves is often easier than adding them. This, in turn, can lead to confusion over whether the o being Romanized is 오 or 어 or the u being Romanized is 우 or 으. Casual users also often omit the apostrophe that differentiates aspirated consonants (ㅋ, ㅌ, ㅍ, and ㅊ) from their unaspirated counterparts (ㄱ, ㄷ, ㅂ, and ㅈ), which can also lead to confusion. Defenders of the McCune-Reischauer system, however, respond that a casual user unfamiliar with Korean can easily approximate the actual pronunciation of Korean names or words even when breves and apostrophes are omitted, although it is still best to include them.
Such common omissions were the primary reason the South Korean government adopted a revised system of romanization in 2000. Critics of the revised system claim it fails to represent 어 and 으 in an easily recognizable way, and that it misrepresents the unaspirated consonants as they are actually pronounced.
Meanwhile, despite official adoption of the new system in South Korea, many in the Korean Studies community, both in and out of South Korea, and international geographic and cartographic conventions generally continue to use either the McCune-Reischauer or Yale system, and North Korea uses a version of McCune-Reischauer. Even within South Korea, usage of the new system is less than universal, as was the case with the variant of McCune-Reischauer that was the official Romanization system between 1984/1988 and 2000.
|Initial consonant of the next syllable|
† An initial consonant before a vowel to indicate absence of sound.
Basically, when deciding whether g or k, b or p, d or t and j or ch is used, use g, b, d or j if it is voiced, and k, p, t or ch if it is not. Pronunciations such as these take precedence over the rules in the table above.
Examples with assimilation:
Examples where pronunciation takes precedence:
ㅝ is written as wo instead of the original system's wŏ in this variant. Because the diphthong w (ㅗ or ㅜ as a semivowel) + o (ㅗ) does not exist in Korean phonology, the South Korean government omitted a breve in wŏ.
Hyphens are used to distinguish between ㄴㄱ and ㅇㅇ in this variant system, instead of the apostrophes in the original version. Therefore apostrophes are only used for aspiration marks in the South Korean system.
Additionally, assimilation-induced aspiration by an initial ㅎ is indicated, e.g. 직할시 (直轄市; "a directly-governed city") is written as chik'alshi, which under the official system is chikhalsi.