The present study was designed to examine the nature of hesitation phenomena in the speech of Korean college EFL learners participating in oral proficiency interviews. Looking beyond the implications of hesitations in language learners' talk as signaling their disfluency and incompetence, this study presents a qualitative analysis to provide insights into the positive aspect of hesitations as a learning opportunity. A detailed qualitative analysis of the learners' talk reveals that hesitation phenomena was abundant in the learners' talk and the underlying mechanisms for the hesitations were more than the learners' incompetence of the target language. Hesitations found in the present study were the places where the learners forestalled, detected, and repaired problems in their target language output. Hesitations were facilitative devices that the learners utilized to make trial and error for further development of their second language. This paper concludes that the hesitation phenomena in learner interactions can be seen as potential opportunities for learning where learners struggle with the target language and learn through those difficulties.