古代朝鮮語
The "Samguk sagi", the "Samguk yusa", and Chinese and Japanese sources transcribe many proper nouns from Silla, including personal names, place names, and titles. These are often given in two variant forms: one that transcribes the Old Korean phonemes, using Chinese characters as phonograms, and one that translates the Old Korean morphemes, using Chinese characters as logograms. This is especially true for place names; they were standardized by royal decree in 757, but the sources preserve forms from both before and after this date. By comparing the two, linguists can infer the value of many Old Korean morphemes.