Good English pronunciation is important for clear communication and avoiding misunderstandings. Thus, this study delves into the challenges faced by students in pronouncing English diphthongs, examining the underlying factors contributing to these difficulties. Diphthongs, characterized by a combination of two vowel sounds within a single syllable, present a significant hurdle for many learners of English as a second language. Through a pronunciation test on ELESP students, this study aims to identify the kinds of English diphthongs that the students find difficult to pronounce.

A Descriptive-quantitative method was employed in this research. The subjects of this study were ELESP Student Batch 2021, consisting of 89 students. Data collection included a pronunciation test to determine the most common mistakes made by students when pronouncing English diphthongs. The data was analyzed quantitatively and using a descriptive method.

The research results showed that the ELESP students of Lambung Mangkurat University still encountered problems in pronouncing several diphthongs. A total of 24.3% mistakes were made by the students, with the diphthongs /e?/ and /??/ exhibiting the least mispronunciations, with 0.8% and 0.9% mistakes respectively. Conversely, the diphthongs /e?/ and /??/ posed the most challenges, with 4.9% and 4.6% mistakes respectively. These findings shed light on the specific difficulties encountered by ELESP students in pronouncing English diphthongs, particularly highlighting the significance of targeted pronunciation instruction to address these challenges and enhance overall phonological proficiency in English.