This study is generally at identifying the errors in the use of inflectional morpheme that was committed by the students and the factors causes of those inflectional morpheme errors. Specifically, the aims of this study focused on identifying the dominant type of errors on the use of inflectional morpheme in students' writing and investigating the possible factors that were caused the errors. The data of this study were obtained and analyzed based on descriptive qualitative research by asking the students to make an essay for an hour. The use of the documentation method was used to collect the data as the result of students' writing. The data of this study was qualitatively analyzed based on the surface strategy taxonomy theory proposed by Dulay et al (1982): the addition error, omission error, misformation, and misordering. In addition, other theories about the factors that were caused errors for the interlingual and intralingual proposed by Richard and Schmidt (2002) The analysis of this study was presented in formal and informal methods. Each problem in this study was descriptively presented for an easier understanding. The finding revealed that the students tended to commit omission errors and addition errors in the use of inflectional morpheme. Furthermore, it was found that these inflectional morpheme errors were caused by the intralingual factors. Moreover, based on the type of intralingual factor, the students were found to commit the errors caused by overgeneralization and ignorance of rules restrictions.

Error Analysis

Inflectional

Students' Writing