The Korean language is usually acknowledged to be a member of the Altaic family and is clearly related to other agglutinative tongues like Turkish, Mongolian, and Japanese. Linguistic unification of the Korean Peninsula apparently followed political unification in the 7th century AD , and today the dialect differences are comparatively slight.
Korean is written with a largely phonetic alphabet called Han'gul. Created in 1443 under the great King Sejong, the Korean alphabet originally consisted of 14 consonants and 10 vowels; since then, 5 consonants and 11 vowels have been added. Han'gul letters are combined into syllables by clustering, in imitation of Chinese characters. Before the invention of Han'gul, Koreans wrote in Chinese, which continued to be both the official language and the language of most literature until the beginning of the 20th century. With the beginning of the Japanese colonial administration in 1910, Japanese became the official language, and the use of Korean was restricted.
Since 1949, the DPRK has used only Han'gul (calling it Choson Muntcha) for writing. North Korean linguists have studied Han'gul extensively, publishing comprehensive dictionaries in 1963 and 1969. In 1964, Kim Il Sung called for purification of Korean by replacing borrowings from English and Japanese with native Korean or familiar Chinese terms. The traditional honorifics of polite language remain in use, though in simplified forms, and have been sanctioned by the government.
Some Chinese (Mandarin dialect) and Russian are spoken in border areas.