Korean language - Wikipedia
https://en.wikipedia.org/wiki/Korean_languageThe core of the Korean vocabulary is made up of native Korean words. However, a significant proportion of the vocabulary, especially words that denote abstract ideas, are Sino-Korean words (of Chinese origin), either: • directly borrowed from written Chinese, or• coined in Korea or Japan using Chinese characters.
History of Korean - Wikipedia
https://en.wikipedia.org/wiki/History_of_KoreanThe traditional periodization of Korean distinguishes: • Old Korean (고대 한국어, 古代韓國語, to 918), the earliest attested stage of the language, through to the fall of Unified Silla. Many authors include the few inscriptions from Silla in the Three Kingdoms period. Authors differ on whether the poorly attested speech of the Goguryeo and Baekje kingdoms and Gaya Confederacy were dialects of Old Korean or separate languages.