This study is conducted based on the reason that Grammar is one of the most important components of a language. It is impossible to learn or use a language without knowing the grammatical rules. Language without grammar causes some problems. Problems in grammar are usually due to the influence of the learners’ native language. Learners need to know the grammatical rules of a language so that they can minimize the transfer of their native grammatical rules.
The writer chooses the students of Writing III class at English Department of IAIN Walisongo Semarang as the subject of the research because they are expected to write grammatically correct writing since they have learnt English for many years. Hence, it is important to know what kinds of grammatical errors that students make and the possible causes of the errors. There are 61 students of Writing III which are divided into two classes; class A and B.
The Purpose of this research is to find out and analyze the grammatical errors as the result of native language interference which are found in students’ compositions. In this research the researcher uses a descriptive analysis or qualitative approach.
The result of this study shows that there are ten types of errors as the result of native language interference, they are errors in the use of: (1) tenses (3.73%), (2) word order (5.82%), (3) articles (10.30%), (4) pronouns (3.13%), (5) linking verbs (13.58%), (6)plurality (21.04%), (7) errors in the use of prepositions (20.90%), (8) subject and verb agreement (20.75%), (9) preference (0.15%), (10) degree of comparison (0.60%). There are four dominant errors; (1) plurality (21.04%), (2) prepositions (20.90%), (3) subject and verb agreement (20.75%), and linking verbs (13.58%). The causes of the errors are divided into two categories; (1) linguistic and (2) non linguistic factors. Linguistic factors include: (a) the lack of students’ understanding on English Grammar, (b) the lack of students’ understanding on English vocabulary, and (c) word to word translation. On the other hand, non linguistic factors include: (a) students’ awareness of learning, (b) psychological motivation, (c) inappropriate teaching methods, and (d) learning environment