Modern Korean language is descended from the language of the Silla Kingdom, which unified the peninsula in the seventh century. As Korean linguist Yi Ki-mun notes, the more remote origins of the Korean language are disputed, although many Korean linguists together with a few western scholars, continue to favor the now widely-contested nineteenth-century theory of an Altaic family of languages supposed to include Korean, Japanese, and Mongolian, among other languages. Although a historical relationship between Korean and Japanese has not been established, modern Korean and Japanese have many similar grammatical features, no doubt in part due to close contacts between the two during the past century. These similarities have given rise to considerable speculation in the popular press. The linguist Kim Chin-wu, for example, has hypothesized that Korea and Japan stood at the end of two routes of large-scale migration in ancient times: a northern route from Inner Asia and southern route from southern China or Southeast Asia. In a variant on the "southern origins" theory of some Japanese scholars, he views the two languages as reflecting disparate "northern" and "southern" influences, with Korean showing more influence from the northern, Inner Asian strain.

Both Korean and Japanese possess what is sometimes called "polite" or "honorific" language, the use of different levels of speech in addressing persons of superior, inferior, or equal rank. These distinctions depend both on the use of different vocabulary and upon basic structural differences in the words employed. For example, in Korean the imperative "go" can be rendered kara when speaking to an inferior or a child, kage when speaking to an adult inferior, kaseyo when speaking to a superior, and kasipsio when speaking to a person of still higher rank. The proper use of polite language, or levels of polite speech, is an extremely complex and subtle matter. The Korean language, like Japanese, is extremely sensitive to the nuances of hierarchical human relationships. Two persons who meet for the first time are expected to use the more distant or formal terms, but they will shift to more informal or "equal" terms if they become friends. Younger people invariably use formal language in addressing elders the latter will use "inferior" terms in "talking down" to those who are younger.

The Korean language may be written using a mixture of Chinese ideograms (hancha) and a native Korean alphabet known as han'gul, or in han'gul alone, much as in a more limited way Indo-European languages sometimes write numbers using Arabic symbols and at other times spell numbers out in their own alphabets or in some combination of the two forms. Han'gul was invented by scholars at the court of King Sejong (1418-50), not solely to promote literacy among the common people as is sometimes claimed, but also, as Professor Gari K. Ledyard has noted, to assist in studies of Chinese historical phonology. According to a perhaps apocryphal decree of the king, an intelligent man could le 10c0 earn han'gul in a morning's time, while even a fool could master it in ten days. As a result, it was scorned by scholars and relegated to women and merchants. The script, which in its modern form contains forty symbols, is considered by linguists to be one of the most scientific ever devised it reflects quite consistently the phonemes of the spoken Korean language.

Because of its greater variety of sounds, Korean does not have the problem of the Japanese written language, which some experts have argued needs to retain a sizable inventory of Chinese characters to distinguish a large number of potentially ambiguous homophones. Since 1948 the continued use of Chinese characters in South Korea has been criticized by linguistic nationalists and some educators and defended by cultural conservatives, who fear that the loss of character literacy could cut younger generations off from a major part of their cultural heritage. Since the early 1970s, Seoul's policy governing the teaching and use of Chinese characters has shifted several times, although the trend clearly has been toward writing in han'gul alone. By early 1990, all but academic writing used far fewer Chinese characters than was the case in the 1960s. In 1989 the Korean Language and Education Research Association, citing the need for Chinese character literacy "at a time when the nation is entering into keen competition with Japan and China" and noting that Japanese educators were increasing the number of Chinese characters taught in elementary schools, recommended to the Ministry of Education that instruction in Chinese characters be reintroduced at the primary-school level.

Although the Korean and Chinese languages are not related in terms of grammatical structure, more than 50 percent of all Korean vocabulary is derived from Chinese loanwords, a reflection of the cultural dominance of China over 2 millennia. In many cases there are two words--a Chinese loanword and an indigenous Korean word--meaning the same thing. The Chinese-based word in Korean sometimes has a bookish or formal flavor. Koreans select one or the other variant to achieve the proper register in speech or in writing, and to make subtle distinctions of meaning in accordance with established usage.

Large numbers of Chinese character compounds coined in Japan in the nineteenth or twentieth centuries to translate modern Western scientific, technical, and political vocabulary came into use in Korea during the colonial period. Post-1945 United States influence has been reflected in a number of English words that have been absorbed into Korean.

Unlike Chinese, Korean does not encompass dialects that are mutually unintelligible, with the possible exception of the variant spoken on Cheju Island. There are, however, regional variations both in vocabulary and pronunciation, the range being comparable to the differences that might be found between Maine and Alabama in the United States. Despite several decades of universal education, similar variations also have been heard between highly educated and professional speakers and Koreans of working class or rural backgrounds. Standard Korean is derived from the language spoken in and around Seoul. More than forty years of division has meant that there are also some divergences in the development of the Korean language north and south of the DMZ.

Data as of June 1990