2004-07-29 高句麗の言語は日本語 インディアナ大学のChristopher Beckwithの近著Koguryo, The Language Of Japan's Continental Relatives: An Introduction To The Historical-comparative Study Of The Japanese Koguryoic Languages With A Preliminary Description Of Archaic Northeastern Middle (BRILL'S JAPANESE STUDIES LIBRARY)によれば高句麗の言語は韓国語より日本語に近い。