Old Korean

Old Korean is the historical variety of the Korean language or Koreanic languages dating from the beginning of Three Kingdoms of Korea to the latter part of the Unified Silla, roughly during the 4th to 10th centuries CE. It is distinct from Proto-Korean (원시 한국어), the ancestral language reconstructed from comparison of Korean dialects. Some linguists propose that Old Korean may have been one of the Altaic languages, although this claim has been controversial.

The extent of Old Korean is unclear. It is generally accepted as including Sillan, which is thought to be the direct ancestor of Middle and Modern Korean, and may also have included Buyeo, Goguryeo, and Baekje. If so, Old Korean was a language family, not a single language. (See Buyeo languages, Koreanic languages.)

Only some literary records of Unified Silla, changed into Goryeo text, are extant and some texts (written in their native Writing system) of the Three Kingdoms period are mostly available in form of inscriptions at present. Thus, the languages of the Three Kingdoms period are generally examined through official government names and local district names. The point at which Old Korean became Middle Korean is assessed variously by different scholars. The line is sometimes drawn in the late Goryeo dynasty, and sometimes around the 15th century in the early Joseon Dynasty. But it is usually thought that Middle Korean started at the establishment of Goryeo, and the standard language of Old Korean was changed from the Silla dialect to the Goryeo dialect.