This is a critical review of C. I. Beckwith’s Koguryo the Language of Japan’s Continental Relatives. The fundamental issue addressed by this book is that of the origins and relationships of the Japanese and Koguryo languages. The author of this book insist Japanese-Koguryoic family of language and he studied of 130 identifiable words and function morphemes from the area of the former Koguryo kingdom are preserved in the Samguk Sagi, or ‘History of the Three Kingdoms’, in toponyms recorded and glossed in the eighth century A.D.
The author of this book try to reconstruct many words and morphemes of archaic and old Koguroic language but he made many mistakes. For examples, the author insist the ‘新羅’, the name of old kingdom in Korean peninsular was pronounced silla, because the Chinese character ‘新’ could be read ‘sir or sil’ at that time as northeastern dialect of Ancient Chinese. But in Samguk Sagi, 新羅 was also written 斯羅, 新 was read by meaning, 斯 was read by its pronunciation, both of them means new nation.