This study reports on how mimicking practice (MP) influences reading aloud and speaking performance. Thirty-eight Japanese university students who participated in this study were instructed to imitate a model reading for four weeks. Data for this study were collected via a pre- post-test design. Students' reading aloud performance was assessed in two ways: (a) how exactly they could imitate the model reading, and (b) how well they could read aloud a short dialogue and an expository text. Students' speaking performance, on the hand, was evaluated by a narration task in which they were asked to describe the events depicted in a series of pictures. The results demonstrated that students' reading aloud performance including mimicking skills was significantly improved in terms of fluency and prosodic features such as stress and intonation. The results also showed that the four-week MP could contribute to the development of fluency in speaking performance.