So far I have reviewed the two controversial opinions of the North Korean and the South Korean linguists concerning the position of the Koguryeo language in the formation of Korean. Many South Korean scholars in favor of the Altaic Language Family Hypothesis argue that the ancient Korean language consisted of two different languages, one of which was the northern dialect including four languages such as the Koguryeo language (the largest one within the area), the Puyo language, the Okche language, the Yemaek language, and the other was the southern dialect, the largest language of which is the Shinla language. On the other hand, the linguists of North Korea claim that in Koguryeo and Shinla the same language was spoken and that modern Korean is formed based on the Koguryeo language. Before evaluating which of these claims is correct I would like to turn to the scarcity of the linguistic data of the Koguryeo language. Compared with the pragmatic methodology of the South Korean linguists in the studies on the Altaic affinity of Korean, the North Korean scholars need to present still more evidences in order to support their argument. In Chung (1993) I argued that studies on the genealogy of the Korean language or history had to be performed regardless of tile political purpose or for the purposes. We should admit the historical fact that there had been many tribal states in the Korean peninsula before the ancient Korean stage, those of which had been emerged to become three kingdoms. Those kingdoms were unified by Shinla, which was connected to Koryeo Dynasty. We cannot disregard the fact that the Korean language has been developed hand in hand with these historical process with those steps related with each age. The first thing we should do right now is to collect the remaining data of the Koguryeo language recorded in the old written materials, which have been found in North Korea as many as possible. Also, 1 hope that the linguists of South Korea achieve more academic success in the comparative studies of the Paekjae language, the Shinla language, and other adjacent Altaic languages.