Hanja
Although a phonetic Korean alphabet, now known as Chosŏn'gŭl or Hangul, had been created by Sejong the Great, it did not come into widespread official use until the late 19th and early 20th century. Thus, until that time it was necessary to be fluent in reading and writing Hanja in order to be literate in Korean, as the vast majority of Korean literature and most other Korean documents were written in Literary Chinese, using Hanja as its primary script. Today, a good working knowledge of Chinese characters is still important for anyone who wishes to study older texts (up to about the 1990s), or anyone who wishes to read scholarly texts in the humanities. Learning a certain number of Hanja is very helpful for understanding the etymology of Sino-Korean words, and for enlarging one's Korean vocabulary. Today, Hanja are not used to write native Korean words, which are always rendered in Hangul, and even words of Chinese origin—"Hanja-eo" ()—are written with the Hangul alphabet most of the time, with the corresponding Chinese character often written next to it in order to prevent confusion with other characters or words with the same phonetics.
Korean language
Korean has numerous small local dialects (called "mal" () [literally "speech"], "saturi" (), or "bang'eon" ( in Korean). The standard language ("pyojun-eo" or "pyojun-mal") of both South Korea and North Korea is based on the dialect of the area around Seoul (which, as Hanyang, was the capital of Joseon-era Korea for 500 years), though the northern standard after the Korean War has been influenced by the dialect of P'yŏngyang. All dialects of Korean are similar to each other and largely mutually intelligible (with the exception of dialect-specific phrases or non-Standard vocabulary unique to dialects), though the dialect of Jeju Island is divergent enough to be sometimes classified as a separate language. One of the more salient differences between dialects is the use of tone: speakers of the Seoul dialect make use of vowel length, whereas speakers of the Gyeongsang dialect maintain the pitch accent of Middle Korean. Some dialects are conservative, maintaining Middle Korean sounds (such as "z, β, ə") which have been lost from the standard language, whereas others are highly innovative.