Abstract:
This research is aimed to describe the errors that the students made in pronouncing English diphthongs and to explain the pronunciations‟ ability of the of the fourth semester students of Muhammadiyah University of Purworejo in the academic year 2015/2016.
This research is designed as descriptive qualitative. The subject of the research is the fourth semester students of English Department of Muhammadiyah University of Purworejo in the academic year of 2015/2016. The subject of the research consists of 27 students. The instrument that is used to get the data is oral test of pronunciation. The techniques of analyzing the data are transcribing, classifying the kind of error, finding out the students‟ score, finding out the students‟ score average, and categorize the students‟ pronunciation ability.
The research finding indicates that the kind of error made by students in pronouncing English diphthong is divided into two. The result shows that 59.65% (114 of 218) of the errors are mispronunciation. On the other hand, 40.35% (104 of 218) of the errors are phonological interference. The result of the data finding shows the average of students‟ score is 73.05. It means that the pronunciation of English diphthong of the fourth semester students of Purworejo Muhammadiyah University in academic year 2015/2016 is good.
