A number of different Korean dialects are spoken in the Korean peninsula. The peninsula is extremely mountainous, and each dialect's "territory" corresponds closely to the natural boundaries between different geographical regions. Most of the dialects are named for one of Korea's traditional Eight Provinces.
The standard language 
- In South Korea, Standard Korean (표준어/標準語) is defined by the National Institute of the Korean Language as "the modern speech of Seoul widely used by the well-cultivated" (교양있는 사람들이 두루 쓰는 현대 서울말). In practice, it tends not to include features that are found exclusively in Seoul.
- In North Korea, the accepted official standard is the Munhwaŏ dialect of Seoul, not the P'yŏng'an dialect -- contrary to popular belief. Though language in the two Koreas have diverged to some extent, the two standards are still broadly intelligible. One notable feature within the divergence is the North's lack of anglicisms 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:
- Hamgyŏng dialects (함경 방언), also called Northeastern dialects. Spoken in the Hamgyŏng (Kwanbuk & Kwannam) region, northeast corner of P'yŏng'an, and Ryanggang Province of North Korea as well as the Yanbian Korean Autonomous Prefecture of northeast China (in Jilin). Nine vowels: the eight of the standard language plus ö.
- Northwestern dialects
- P'yŏng'an dialects (평안방언). Spoken in P'yŏngyang (though not the basis of the official language), the P'yŏng'an region, Chagang Province, and neighboring Liaoning Province of China.
- Hwanghae dialects (황해 방언). Spoken in the Hwanghae (Haesŏ) region of North Korea. Commonly included among the Central dialects, but do not fit there comfortably.
- Yukchin dialect. Spoken in the historical Yukchin area of northern North Hamgyŏng province, far removed from P'yŏng'an, but has more in common with P'yŏng'an dialects than with the surrounding Hamgyŏng dialects.
- Central dialects. Commonly divided along provincial boundaries:
- Seoul dialect (서울말), also called Gyeonggi. Spoken in Gyeonggi, Incheon, Seoul (South Korea), and Kaesŏng (North Korea). The basis of the standard language.
- Yeongseo dialects (영서 방언). Spoken in the Yeongseo region of Gangwon Province in South Korea and neighbouring Kangwŏn Province in North Korea, to the west of the Taebaek Mountains. Though commonly subsumed under Gangwon dialect (강원 방언), Yeongseo is quite distinct from the Yeongdong dialects to the east of the mountains.
- Chungcheong dialects (충청 방언). Spoken in the Chungcheong(Hoseo) region of South Korea, including the city of Daejeon.
- Yoengdong dialects (영동 방언). Spoken in the Yeongdong region of Gangwon Province in South Korea and neighbouring Kangwŏn Province in North Korea, to the east of the Taebaek Mountains. Though commonly subsumed under Gangwon dialect (강원 방언), Yeongdong is quite distinct from the Central Korean dialects to the west of the mountains.
- Gyeongsang dialects (경상 방언), also called Southeastern dialects. Spoken in Gyeongsang (Yeongnam) region 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 dialects (전라 방언), also called Southwestern dialects. Spoken in the Jeolla (Honam) region of South Korea, including the city of Gwangju. Ten vowels: i, e, ae, a, ü, ö, u, o, eu, eo.
- Jeju dialect (제주 방언) is spoken on Jeju Island, off the southwest coast of South Korea, and is sometimes considered a separate Koreanic language. The nine vowels of Middle Korean, including arae-a (ɔ). May have additional consonants as well.
Outside of the Korean peninsula 
- Koryo-mar (Autonym: Корё мар/고려말, Standard Korean: 중앙아시아 한국어), usually identified as a descendant of the Hamgyŏng dialect, is spoken by the Koryo-saram, ethnic Koreans in the former USSR. It consists of a Korean base vocabulary, but takes many loanwords and calques from Russian and the Turkic languages.
- Zainichi Korean language (재일어; 재일조선어) is a language or a dialect spoken among Zainichi Koreans in Japan, strongly influenced by Japanese.
- As discussed above, Koreans in China use a dialect nearly identical to Hamgyŏng dialect in North Korea, but there are still some differences, as the former has many modern terms that came from Chinese.
See also 
- Korean language North-South differences
- Koreanic languages
- List of Korea-related topics
- Eight Provinces (Korea)
- Regions of Korea
- Tsushima dialect of Japanese, which contains loanwords from Korean.
- Lee & Ramsey, 2000. The Korean language
- Janhunen, Juha, 1996. Manchuria: an ethnic history