The relationship of the Japanese and Korean languages is a difficult issue for linguists. Some classify Japanese as a language isolate and Korean as a member of the Altaic language family. Others, however, consider Japanese and Korean to be related and some claim that they should both be classified as members of the Altaic language family. The more I learn about these two languages, the more I am convinced that they are probably distantly related
The two languages both lack tone, unlike many other Asian languages. They have similar syllable structures which usually consist of a consonant and a vowel. They share the same word order of subject, verb and object. They are pro-drop languages- this means that the personal pronoun can be dropped when the meaning is clear.
Both Japanese and Korean have subject markers, object markers and topic markers. I know of no other languages which make use of all three. Verbs are used in combination with a variety of endings to indicate the relationship between the speaker and the listener. The question marker is "ka" in Japanese and "kka" in Korean. The two languages can express a wide range of degrees of politeness. One ending, -yo, not only expresses a neutral degree of politeness but is also an exclamatory form in both languages. The plain form of the verb "be" is the same in both languages- "da". This is exemplified by the sentence "It's a book". In Japanese this is "Hon da" and in Korean it is "Chaegi da".
Japanese and Korean have postpositions, some of which are remarkably similar in the two languages. For example, the postposition -e means "in" in Korean and "to" in Japanese.
They also treat many verbs similarly to adjectives. The sentence "It was cold" is formed from the adjective "cold" which is inflected as if it were a verb because it is given a past tense ending.
Sergei Storastin observed that there may be a 25% rate of potential cognates in the Swadesh word list. The Swadesh word list is a collection of words which are considered basic and useful for determining the degree to which languages are related. The languages in the Swadesh word list are words which are considered to be native words. In other words, it is considered unlikely that they would be borrowed. Words such as "water" and "be" are considered basic words and thus likely native words. In Japanese, "water" is "mizu" and in Korean it is "mul". The verb "be" is also similar in these two languages. The Japanese word for "be" is "iru" and the Korean word is "ida".
A comparison of Japanese and Korean reveals an amazing number of similarities. For political and nationalistic reasons, many Japanese and Koreans reject the idea that the two languages could be related. However, upon examination of the evidence, it appears likely that the two languages are related to one another. Without a common writing system to unify them, it would have been easy for them to drift far apart from one another, especially if they separated a very long time ago. The similarities that they share appear too great to be merely a coincidence.