Abstract:
This study aimed at investigating difficulties faced by students in using affixes on vocabulary learning. The researcher adopted descriptive analytical method. Two instruments were used for collecting data relevant to the study, namely questionnaire to teachers of English at some Sudanese Universities and written diagnostic test for the first year students majoring English at Sudan University of Science and Technology, College of Languages. The study sample of questionnaire comprises (20) teachers whereas the written diagnostic test composes (30) students. The researcher applied SPSS programme to analyze and verify the hypotheses. The results showed that vocabulary learning can help students in promoting morphological competence. Moreover, the students can acquire a large number of foreign language vocabularies simply by learning affixes. The study recommended that instructors should raise students' awareness about the importance of vocabulary learning. On the other hand, the teachers should encourage students to use notebook to write down vocabulary learning. Some suggestions were made for further studies.