A number of Korean dialects are spoken on the Korean Peninsula. The peninsula is extremely mountainous and each dialect's "territory" corresponds closely to the natural boundaries between different geographical regions of Korea. Most of the dialects are named for one of the traditional Eight Provinces of Korea. One is sufficiently distinct from the others to be considered a separate language, the Jeju language.
In South Korea, Standard Korean is defined by the National Institute of the Korean Language as "the modern speech of Seoul widely used by the well-cultivated". In practice, it tends not to include features that are found exclusively in Seoul.
Despite North–South differences in the Korean language, the two standards are still broadly intelligible. One notable feature within the divergence is the North's lack of anglicisms and other foreign borrowings due to isolationism and self-reliance—pure/invented Korean words are used in replacement.
Regional dialects
Korea is a mountainous country, and Korean is consequently divided into numerous small local dialects. There are few clear demarcations, so dialect classification is necessarily to some extent arbitrary. Nonetheless, the following divisions are commonly cited in the literature:
*Ryukchin dialect : Spoken in the historical Yukchin region which is located in the northern part of North Hamgyong Province, far removed from P'yŏng'an, but has more in common with P'yŏng'an dialects than with the surrounding Hamgyŏng dialects. Since it has been isolated from the major changes of Korean language, it has preserved distinct features of Middle Korean. It is the only known tonal Korean language.
Northwestern dialects
*Pyongan dialect: spoken in Pyongyang, Pyongan Province, Chagang Province, and neighboring Liaoning, of China. The basis of the standard language for North Korea.
Central dialects. Commonly divided along provincial boundaries:
*Gyeonggi dialect, also called the "Seoul dialect": spoken in the Gyeonggi Province, Seoul and Incheon cities, as well as southeastern Kaesong. The basis of the standard language for South Korea.
*Yeongdong dialects: spoken in Yeongdong, Gangwon Province and neighbouring Kangwon Province to the east of the Taebaek Mountains. Yeongdong is quite distinct from the Central Korean dialects to the west of the mountains.
*Hwanghae dialect: spoken in Hwanghae Province of North Korea. Commonly included among the Central dialects, but some researchers argue that it does not fit there comfortably.
Gyeongsang dialects, also called Southeastern dialects: spoken in Gyeongsang Province of South Korea, including the cities of Busan, Daegu and Ulsan. This dialect is easily distinguished from the Seoul dialect because its pitch is more varied. Six vowels, i, e, a, eo, o, u.
Jeolla dialect, also called Southwestern dialects: spoken in the Jeolla Province region of South Korea, including the city of Gwangju. Ten vowels: i, e, ae, a, ü, ö, u, o, eu, eo.
Jeju language is spoken on Jejudo off the southwest coast of South Korea and is sometimes considered a separate Koreanic language. The nine vowels of Middle Korean, including arae-a. May have additional consonants as well.
A recent statistical analysis of these dialects suggests that the hierarchical structure within these dialects are highly uncertain, meaning that there is no quantitative evidence to support a family-tree-like relationship among them.
Koryo-mar, usually identified as a descendant of the Hamgyŏng dialect, is spoken by the Koryo-saram, ethnic Koreans in the post-Soviet states of Russia and Central Asia. It consists of a Korean base vocabulary, but takes many loanwords and calques from Russian language. It is mostly based on Hamgyong and Ryukchin dialect, since Koryo-saram people are mainly from the northern part of Hamgyong region.
Some researchers classify the Korean dialects in Western and Eastern dialects. Compared with Middle Korean, the Western dialects have preserved long vowels, while the Eastern dialects have preserved tones or pitch accent. The Jeju language and some dialects in North Korean make no distinction between vowel length or tone. But the Southeastern dialect and the Northeastern dialect may not be closely related to each other genealogically.
