With the spread of mobile devices, mobile phones have enormous potential regarding their pedagogical use in language education. The goal of this study is to analyse user experience of a mobile-based learning system that is enhanced by speech recognition technology for the improvement of EFL (English as a foreign language) learners' speaking proficiency. "Speaking English 60 Junior," which is developed for middle-school students in Korea, is equipped with automatic speech recognition (ASR) for students' self-regulated speaking practice. Open-ended survey questions were used to gain insight into users' reactions. The results showed that the students, overall, had positive attitudes towards the use of the application for learning to speak. They particularly expressed great interest in the speech recognition function because it immediately demonstrated the consequence of their speech input. The speech-interactive activity, in which they interacted with a virtual character via ASR, also received positive comments. The findings highlight the potential use of mobile phones and ASR for learning to speak in the EFL context. Recommendations for future research are discussed based on the results of this study.