Since Vietnam has opened its door to the rest of the world, more and more people with their wish to join world trends have rushed to learn foreign languages, especially English. This demand in language learning has brought about a great amount of positive changes in language teaching in Vietnam. Language teachers have looked for and tried different methods and techniques in teaching and learning in order to find the effective ones. The effectiveness of a teaching method or technique is reflected in the learners’ language competence that is their abilities to perform the four language skills: Reading, Listening, Writing and Speaking. Amongst these skills the two productive skills, writing and speaking, are considered more difficult than the others as the learners need to use the language to convey their messages comprehensibly and accurately in real life communication. When a message is unsuccessfully conveyed, the factor, which is most likely to be blamed for is errors in the use of the language.
It is natural in language teaching that learners make mistakes and errors when writing in English. How to cope with and when to give feedback to these errors are vital in teaching language as it may either result in motivation or discouragement in language learning. Some teachers’ concern is directed to contrastive analyses of Vietnamese and English with the hope to predict and prevent errors before they appear. This theory has been supported by Lado (1957). However, Richards (1971) in his research found out that apart from the first language interference, there were other causes which are products of intra-lingual analogies such as overgeneralization, incomplete application of rules or ignorance of rule restrictions as well as false concepts hypothesized. So far, there has been scarily any research on the causes of errors in students’ writing in English in Vietnamese universities. Therefore, I am attempted to carry out a research study applying error analysis in clarifying learners’ errors in the use of cohesive devices in writing at Thang Long University as “cohesive devices are crucial in writing” ( Zamel,1983:1).