The purpose of this study is to explore effective ways to use technology to promote independent learning growth among second language learners. Specifically, the study focuses on second language learners' acquisition of understandable pronunciation so that they can speak with confidence. Speaking confidently is an extremely important skill in real-life communication. Pronunciation is a serious concern for Japanese learners, yet not enough time is spent on it in the classroom. The meaning of this study is to find ways to enhance the ability of second language learners to acquire comprehensive pronunciation independently. Currently, I am working on the development of a pronunciation evaluation system. One of the features of this system is that, in addition to automatic feedback by the machine, it will be equipped with a function that allows the learners to perform self-assessment by using five criteria so that the learners can understand what pronunciation features they are confident with. Furthermore, the system will be able to provide pronunciation practice based on texts of interest to the learner through free input. Through this integrated approach, I expect learners to acquire understandable pronunciation autonomously.