In this research, I examined the relative difficulty of typical errors made by Korean students who learn Japanese language, their sources, and the differences of students and instructors' judgment about the error sources. The followings are the main f ...

In this research, I examined the relative difficulty of typical errors made by Korean students who learn Japanese language, their sources, and the differences of students and instructors' judgment about the error sources. The followings are the main findings.
(1) In the test, in which students were asked to correct the common errors made by Korean students who learn Japanese language, the 4th year students, who are in the higher level, scored higher than the 3rd year students in lexicology errors, morphology errors, syntactics･semantics errors but scored lower in phonology (pronunciation) errors; it's because they ignored long vowel sounds in writing adopted words. In generation, they, the 3rd and the 4th year students, scored good points in morphology errors, phonology errors, syntactics･semantics errors, lexicology errors respectively.
(2) In all the error categories, the rate of error caused by something other than Korean language interference was higher than that of error by Korean language interference; however, the difference is relatively less obvious in phonology errors. Most of these errors were made by the interference inside of the Japanese language; there are the errors caused by the difficulties of Japanese language itself and the errors made by overgeneralization.
(3) According to the error categories, the differences in the judgment about the error sources were shown between the students and the instructors in the following areas - the errors made by the difficulties of Japanese language structure (phonology error category) between the 3rd year students and the instructor, the errors made by Korean language interference, the errors made by the difficulties of Japanese language structure (lexicology error category) between the 4th year students and the instructor, the errors made by the difficulties of Japanese language structure, the errors made by not being taught (morphology error category) between the 3rd year students and the instructor, and the induced errors (syntactics･semantics error category) between the 4th year students and the instructor.